GTX 295 for Bootcamp, 8800GT for OSX

[punkmofo]

Hello All,

I was searching this forum for GTX 295, but I didn't find what I was looking for, it's a pretty new card so no surprise there. I did find a similar topic about the 4870X2 from a couple of months ago, but I'm not 100% clear if the same applies to this card. If this has already been covered in detail, I apologize, and please point me in the right direction:

I have an early 2008 2.8Ghz, and Vista64 is running great on a separate hd (Samsung Spinpoint F1). I'd like to upgrade to a GTX 295 to use with Vista, and still be able to use OSX. I just want to make sure I have my facts straight. I ordered one of these (http://shop.ati.com/product.asp?sku=3280778) cables from ATI a while ago, is that what I need to get this up and running? And is there an easy way to keep the 8800GT as well to run Mac OSX (without using the optical drive power) or do I need to replace it with a 2600XT for this setup to work? I'd hate to get rid of the 8800GT if all I need is another cable (or two) to get both cards working.

Thanks in advance for any advice. Thoughts?

[macest]

You will require three power feeds for the 8800 + 295 setup. The 8800 requires one 6-pin, the 295 requires one 6-pin and one 8-pin. The Mac Pro only has two PCI-E power connectors on the motherboard, therefore you cannot run the configuration you want off of those alone.

The ATI solution won't work because you can't run an ATI card and NVIDIA card simultaneously in Windows. The only option I can see working is using the spare molex connector from the optical bay.

[peskaa]

You will require three power feeds for the 8800 + 295 setup. The 8800 requires one 6-pin, the 295 requires one 6-pin and one 8-pin. The Mac Pro only has two PCI-E power connectors on the motherboard, therefore you cannot run the configuration you want off of those alone.

The ATI solution won't work because you can't run an ATI card and NVIDIA card simultaneously in Windows. The only option I can see working is using the spare molex connector from the optical bay.

Can you jack power from one of the optical bays if you have a SuperDrive in each? (like in a PC when you run a fan off the molex, as well as the drive), or does that overload the connection?

[macest]

Can you jack power from one of the optical bays if you have a SuperDrive in each? (like in a PC when you run a fan off the molex, as well as the drive), or does that overload the connection?

You could use molex splitter, but I wouldn't advise it. I don't think a single molex cable supplies enough power for a 6-pin connector (molex to 6-pin cables usually have two molex inputs on them), let alone powering a superdrive as well.

[punkmofo]

You will require three power feeds for the 8800 + 295 setup. The 8800 requires one 6-pin, the 295 requires one 6-pin and one 8-pin. The Mac Pro only has two PCI-E power connectors on the motherboard, therefore you cannot run the configuration you want off of those alone.

The ATI solution won't work because you can't run an ATI card and NVIDIA card simultaneously in Windows. The only option I can see working is using the spare molex connector from the optical bay.

OK, that makes sense, thanks for the reply. Should I be worried about using the connector from the optical bay for the 8800, if I don't need it for anything else? I'm assuming the PSU can handle the load with both cards.

-- nevermind, I think you answered that above.

[peskaa]

You could use molex splitter, but I wouldn't advise it. I don't think a single molex cable supplies enough power for a 6-pin connector (molex to 6-pin cables usually have two molex inputs on them), let alone powering a superdrive as well.

So with the normal set up (ie: single installed SuperDrive) the power comes from a single molex socket on the logic board to the 6/8-pin on the GPU?

[punkmofo]

I'm going to try this tonight, I'll let you know how it works out. If I can do it, it must be pretty easy :)

[Cindori]

http://forums.macrumors.com/showthread.php?t=418279

[punkmofo]

Well, the good news is I got the GTX 295 running in Windows Vista with no problems. The 8800GT that came with my mac is connected using the optical drive power. The bad news: when I try to boot OSX I get a kernel panic. After trying that I would get a black screen in Vista unless I disconnected power from the 8800GT.

update: still no luck in OSX. At first I could see both cards in Device Manager. Now I only see the gtx 295 and if I have both cards connected, no picture at all.
Any ideas?

[sneezymarble]

Have you thought about buying a separate PSU for the 295? I'd leave the 8800GT on the native PSU and get at least a 700W PSU to power the 295. Since you won't be able to plug the second PSU into the motherboard you'll need to mod the 24 pin motherboard connector so that you can turn the second PSU on with either the switch on the unit or by adding your own switch. Both options are easy to do. Using the switch on the PSU unit is easier. Instructions. (http://www.overclock.net/faqs/15751-info-can-i-use-two-power.html) Good luck.

[punkmofo]

A second PSU is an interesting idea, hopefully it doesn't come to that. My goal is to dual boot while having the correct card recognized automatically for each OS. I've got this working in OSX but not Vista (this is paraphrased from a thread on the nvidia forums):

"I don't think it's a power issue. [the 980W PSU] is well within spec to run both cards. After tinkering a bit (updated EFI firmware) I can boot OSX and Windows now with both cards (I'm using Vista 64, not XP). Vista is booting fine, but it seems to be defaulting to the 8800 after running OSX. I tried just switching the monitor cable between cards for a quick check to see which one it's using. In Windows, with the cable plugged into the GTX, I get no image (after using OSX). If I disconnect the power supply to the 8800 and reboot it uses the GTX. OSX now seems to be able to figure it out and uses the 8800GT with power connected to both cards."

I'm gonna play around with this some more tonight.

[UltraNEO*]

Well, the good news is I got the GTX 295 running in Windows Vista with no problems. The 8800GT that came with my mac is connected using the optical drive power. The bad news: when I try to boot OSX I get a kernel panic. After trying that I would get a black screen in Vista unless I disconnected power from the 8800GT.

update: still no luck in OSX. At first I could see both cards in Device Manager. Now I only see the gtx 295 and if I have both cards connected, no picture at all.
Any ideas?

When you get a blank screen, what happens when you tap on the keyboard a few times? By default Windows will use the 8800GT as it's main videocard until such time you tell it otherwise...

Depending on which version of windows your using, it'll hate having more than one card!! Try disabling the 8800GT in device manager.

[IEatApples]

I'm gonna play around with this some more tonight.
Keep us posted… I'd love to do this myself… if it works. :);)

[punkmofo]

When you get a blank screen, what happens when you tap on the keyboard a few times? By default Windows will use the 8800GT as it's main videocard until such time you tell it otherwise...

Depending on which version of windows your using, it'll hate having more than one card!! Try disabling the 8800GT in device manager.

Yeah, it definitely does not like it. I don't think I touched the keyboard, I'll give that a shot. I did try disabling the 8800GT and then freaked out when both OSX and Vista didn't boot. After a couple of tries I got Vista to boot in safe mode, then OSX worked again... but that had me worried. I'll try again since I updated the firmware - I don't even know if that's related at all but OSX is booting fine with both cards hooked up since I did that.

[bumble-bee]

Hi, what about the 295gtx fan's, are they runing at full power under os x?

Keep on trying :rolleyes:

Greetings

[mattcube64]

Good luck punkmofo, and keep us updated!

I need a good gaming computer, but need OSX for school stuff. I'd love to get a Mac Pro, but the only way I'd consider it is to be able to install a GTX 295 like you're doing!

I'm anxious to see if you can get it to work!

EDIT: And do you mind taking a pic of the interior of your computer. I'd love to see what a 8800 and 295 look like together in the Mac Pro!

[nanofrog]

If anyone is interested in the logic board power cable internationally, look here (http://www.svideo.com/x1900.html).

[alam]

If anyone is interested in the logic board power cable internationally, look here (http://www.svideo.com/x1900.html).

tnx :D i'll need those to ship it to my country

[punkmofo]

Hi, what about the 295gtx fan's, are they runing at full power under os x?

Nope, the fans go full tilt for a few seconds when the machine starts up, other than that they're pretty quiet. The GTX is a little louder than the 8800GT though, which is pretty much silent most of the time.

Good luck punkmofo, and keep us updated!

I need a good gaming computer, but need OSX for school stuff. I'd love to get a Mac Pro, but the only way I'd consider it is to be able to install a GTX 295 like you're doing!

I'm anxious to see if you can get it to work!

EDIT: And do you mind taking a pic of the interior of your computer. I'd love to see what a 8800 and 295 look like together in the Mac Pro!

No problem, but it'll have to wait a couple of days, the camera's at work right now. I have a giant glowing blue cable going from the 8800 through the top of the optical bay, and the side panel off - until I work up the patience to fish the power through properly (Why is that hole so small?).

Anyway folks, everything seems to be running. After disabling the 8800GT I installed the 181.22 drivers again, then had to start in safe mode (because that killed everything). Now finally Vista also works with both cards plugged in. I played a few minutes of Crysis Warhead with everything on 'Enthusiast' and 4xAA to make myself feel better. Unfortunately I had to return one of the DVI cables to work today so I just need to pick up a new one for the final test. Sweet. I'll keep you posted.

[mattcube64]

Nope, the fans go full tilt for a few seconds when the machine starts up, other than that they're pretty quiet. The GTX is a little louder than the 8800GT though, which is pretty much silent most of the time.



No problem, but it'll have to wait a couple of days, the camera's at work right now. I have a giant glowing blue cable going from the 8800 through the top of the optical bay, and the side panel off - until I work up the patience to fish the power through properly (Why is that hole so small?).

Anyway folks, everything seems to be running. After disabling the 8800GT I installed the 181.22 drivers again, then had to start in safe mode (because that killed everything). Now finally Vista also works with both cards plugged in. I played a few minutes of Crysis Warhead with everything on 'Enthusiast' and 4xAA to make myself feel better. Unfortunately I had to return one of the DVI cables to work today so I just need to pick up a new one for the final test. Sweet. I'll keep you posted.

Awesome, thanks!

So, does that mean you have both cards installed at the same time. Vista is automatically using the 295, and OSX is automatically using the 8800? No crazy loops you have to jump through?

[punkmofo]

I won't know for sure until I pick up another dvi cable. But it is booting both OS's with power going to both cards, which is a step up. I only have one monitor cable at the moment so it's automatically using whichever card I plug it into.

[bumble-bee]

Punkmofo, can u post a screenshot of your system-profiler,
which shows how the 295gtx is listed in Mac OS X?
Did u modify the drivers of Mac OS X?

And that I understand u right, under Mac OS X the 295GTX in idle mode is as loud as the 8800gt? unbelievably!!!:eek:



I won't know for sure until I pick up another dvi cable. But it is booting both OS's with power going to both cards, which is a step up. I only have one monitor cable at the moment so it's automatically using whichever card I plug it into.

[punkmofo]

And that I understand u right, under Mac OS X the 295GTX in idle mode is as loud as the 8800gt? unbelievably!!!:eek:

Not exactly - what I said was "The GTX is a little louder than the 8800GT". It's quieter than I expected for such a huge beast, and not running very hot at all. It isn't any louder in OSX than it is in Windows. It definitely doesn't have the annoying airplane engine whine of the 8800GT which gets really loud as you crank up the speed. I was using rivatuner to adjust the fan speed on the 8800 but I stopped because I was getting some weird results.

Edit: No, I haven't modified any drivers.

Here are some screenshots. As you can see, Windows has no problem recognizing both cards. OSX has no idea what to make of the gtx 295. I'm hoping this might change with 10.6.

[punkmofo]

... I thought it was interesting that the gtx shows up twice in the device manager. Here's another screenshot showing the gtx 295 specs in the appearance control panel.

[bumble-bee]

Thanks for the screenshots,
I see that u have mounted the 8800gt in Slot 1, and the 295gtx above.

I think only slot 1 is a the pci-e 16x slot, above there are three slots with 4x and 8x.

Wouldn't it be better to mount the 295gtx in slot 1 to get the full power of the beast, an mount the 8800 in a 4x or 8x slot??

I mean this:
Go to /system/Library/CoreServices/Expansion Slot Utility
There u can configure the slots.

Bumble-bee

... I thought it was interesting that the gtx shows up twice in the device manager. Here's another screenshot showing the gtx 295 specs in the appearance control panel.

[punkmofo]

This is from the Apple support site:

"The Mac Pro (Early 2008) computers implement PCI-E revision 2.0 which support twice the data rate per lane as the PCI Express revision 1. Slots 1 and 2 are both x16 revision 2.0 slots. Slots 3 and 4 are both x4 revision 1 slots.

The number of lanes for each of these slots is permanently set for the Mac Pro (Early 2008). The Expansion Slot Utility doesn't apply."

So the expansion slot utility doesn't work on my mac, does that also mean the gtx has to physically be in the first slot to get the full benefit? I interpreted this to mean slots 1 and 2 could take x16 cards. I just assumed I was getting full power in Windows based on the results I got in Crysis, which seem to be dead-on with benchmarks (http://www.hardocp.com/article.html?art=MTYwOCw0LCxoZW50aHVzaWFzdA==) I've read for this card...

Does the following apply to the Early 2008 Mac Pro as well? "Only one slot actually has 16 lanes going to it—you can put a x16 card into a slot that is only using one lane and it will operate properly, but it will operate more slowly than the same card in a x4, x8 or x16 slot." And what are the implications if the 8800 is disabled in Windows?

[IEatApples]

Ok… so can you let us know when things are working "perfectly"? … + Add a step by step guide (with pictures if possible…*I'm stupid…need help) ;):D

[punkmofo]

I'll be sure to let you know when I get it all working.

Can anyone shed any light on the PCIe x16 slot question above?

[bumble-bee]

Hi again,
i think u have no slot problem, because u have the early 2008 version of the macpro. I got the 2007 macpro, a there u have a slot "problem".

Do u think the 295gtx can also be mounted in the first slot?
If it is possible and bootable, i would go and by myself this graficmonster.



I'll be sure to let you know when I get it all working.

Can anyone shed any light on the PCIe x16 slot question above?

[Tallest Skil]

The Penryn Mac Pro has two PCIe 2.0 16x slots.

No Expansion Slot Utility, but 1 and 2 are both 16x.

[punkmofo]

Cool, thanks guys. I thought so but sometimes it's good to get corroboration from someone smarter than me. :)

[diamond.g]

... I thought it was interesting that the gtx shows up twice in the device manager. Here's another screenshot showing the gtx 295 specs in the appearance control panel.

Yeah the way the card "announces" itself to the computer is as two separate chips. ATI figured out how to make their X2 variants "announce" itself as one GPU.

That is probably why OS X has no idea what to do with it. It doesn't know what single card SLI is. ATI never exposes that.

[punkmofo]

SCENARIO A (aka "I'm a Mac"): OSX boots just fine every time with both cards powered and hooked up to the same monitor.

SCENARIO B (aka "I'm a PC") Booting Vista gets... random results:

1. Same setup as above, occasionally it works and defaults to the 8800 in slot 1. Usually the gtx is auto-disabled by Windows, claiming it's conflicting with a vga driver (?). Vista won't let me manually install the NEC driver on the "secondary" display, which also shows up as the same vga type you get when in safe mode. Or I might just get a blank screen.

2. 50-50 chance it will work with both cards powered, enabled and one physically connected to the monitor. Secondary display shows up as generic PNP monitor. This I could live with but it's not consistent.

3. The only truly consistent result in Vista is with only one card powered. Not bad, but not great.

4. Disabling the 8800 in slot 1 usually either fails to boot Vista or boots but fails to load the gtx adapter drivers, again as if it was in safe mode. I haven't tried the 8800 in PCIe slot 2 yet. I'm not comfortable with that setup because the 8800 blocks the fan from the gtx. This might solve the random booting issue though.

Question: Is it even possible to allow two cards to connect to the same monitor in Vista (Card 1: DVI-D port, Card 2: DVI-I port)? I can see why this wouldn't work.

[bumble-bee]

Hi,
have u make some steps forward,

Or still Problems with Windows?

Please keep us updated.

[evildede]

If I'd buy a GTX 295 and I'd switch card every time I wanna use windows, it would work fine, right? Is there anything special I need to do to make it work properly, like anything about connectors I need to know? I'd like to do some heavy gaming but I don't feel like having to sell my Mac Pro to get the nehalem ones coming out later this year with hopefully a better card, and at the same time I doubt Apple will be offering something as good as the GTX 295.

[punkmofo]

Good news: Vista 64 is now running smoothly with the gtx295 in slot 1 and the 8800 in slot 2. The 8800 is powered but the monitor cable is not connected. I only plug the 2nd cable in to boot OSX. Vista takes a very long time to boot (1-2 minutes) when power is connected to both cards. It doesn't seem to matter which slot the 8800 is in, that card is the default primary display every time. I have monitor 3 designated as the primary display in order for it to use the 295, and recognize my monitor's driver. OSX just works.

The gtx fan runs steadily but not loudly. It does seem warmer with the bigger card in slot 1, but the other way it was basically wasting a pci slot. Disabling the 8800 results in the drivers not loading for the 295.

Overall the gtx295 feels less stable than the 8800GT, mostly I think this is due to driver issues. The gtx285 OC or black edition might be a safer (and cheaper) bet to avoid dual-gpu hassles. However, since upgrading to 182.06 drivers I'm seeing some big improvements in stability over 181.22. As I've mentioned before, I'm getting a smooth 28-35 fps in Crysis Warhead at 1920x1200 with all settings at 'enthusiast', and 4xAA. However, in my heavily modded version of Oblivion I'm still getting a brutal 3fps in some areas and freezing and stuttering at the same settings. Other games I've tested (The Witcher, NWN2, AOC) are all running well on max settings.

[bumble-bee]

Hi everybody, has anyone tried this on a 1. Generation MacPro (quadcore) model?


CU

[Cindori]

Hi everybody, has anyone tried this on a 1. Generation MacPro (quadcore) model?


CU


There is no point in it, you can only have 8x (instead of 16x) speed on your GTX295.

[alam]

Good news: Vista 64 is now running smoothly with the gtx295 in slot 1 and the 8800 in slot 2. The 8800 is powered but the monitor cable is not connected. I only plug the 2nd cable in to boot OSX. Vista takes a very long time to boot (1-2 minutes) when power is connected to both cards. It doesn't seem to matter which slot the 8800 is in, that card is the default primary display every time. I have monitor 3 designated as the primary display in order for it to use the 295, and recognize my monitor's driver. OSX just works.

The gtx fan runs steadily but not loudly. It does seem warmer with the bigger card in slot 1, but the other way it was basically wasting a pci slot. Disabling the 8800 results in the drivers not loading for the 295.

Overall the gtx295 feels less stable than the 8800GT, mostly I think this is due to driver issues. The gtx285 OC or black edition might be a safer (and cheaper) bet to avoid dual-gpu hassles. However, since upgrading to 182.06 drivers I'm seeing some big improvements in stability over 181.22. As I've mentioned before, I'm getting a smooth 28-35 fps in Crysis Warhead at 1920x1200 with all settings at 'enthusiast', and 4xAA. However, in my heavily modded version of Oblivion I'm still getting a brutal 3fps in some areas and freezing and stuttering at the same settings. Other games I've tested (The Witcher, NWN2, AOC) are all running well on max settings.

can you give us some explanation with pictures or videos about the hardware setup you made because it's really interesting & i want to try it out, but i don't understand how did you do it??

[punkmofo]

can you give us some explanation with pictures or videos about the hardware setup you made because it's really interesting & i want to try it out, but i don't understand how did you do it??

Sure, I've been meaning to do that, just busy lately. I should have time this week to take some pics.

After a week with this setup, I should probably clarify something I said earlier:

It's quieter than I expected for such a huge beast, and not running very hot at all. It isn't any louder in OSX than it is in Windows.

... this only applies to OSX. I downloaded GPU-Z to check the actual temp in Vista with the 295... Idle temperature is 51C, fan speed 41%. After 1 hour of Crysis Warhead, my temp hit 88C (!), and the fan was up to 79%. This is with the side panel off. After reading a bit more, that's not unusual for this card but that seems crazy hot to me. Previously, the 8800 rarely got hotter than 65C after running for several hours. (Next project: gtx 295 h2O?)

This is interesting too: at first I thought something was wrong with the clock reading, but the gtx seriously clocks itself down when idle, which is great. It goes down to 300Mhz (core) and 100 Mhz (memory).

There is no point in it, you can only have 8x (instead of 16x) speed on your GTX295.

I thought you could designate 1 slot to have 16 lanes in the 1st gen Mac Pro...

[alam]

Sure, I've been meaning to do that, just busy lately. I should have time this week to take some pics.

After a week with this setup, I should probably clarify something I said earlier:



... this only applies to OSX. I downloaded GPU-Z to check the actual temp in Vista with the 295... Idle temperature is 51C, fan speed 41%. After 1 hour of Crysis Warhead, my temp hit 88C (!), and the fan was up to 79%. This is with the side panel off. After reading a bit more, that's not unusual for this card but that seems crazy hot to me. Previously, the 8800 rarely got hotter than 65C after running for several hours. (Next project: gtx 295 h2O?)

This is interesting too: at first I thought something was wrong with the clock reading, but the gtx seriously clocks itself down when idle, which is great. It goes down to 300Mhz (core) and 100 Mhz (memory).



I thought you could designate 1 slot to have 16 lanes in the 1st gen Mac Pro...

tnx and i'll be waiting until your free to tell us the way you did it & also i hope these temperature numbers gets lower in some way
good luck :rolleyes:

[diamond.g]

... this only applies to OSX. I downloaded GPU-Z to check the actual temp in Vista with the 295... Idle temperature is 51C, fan speed 41%. After 1 hour of Crysis Warhead, my temp hit 88C (!), and the fan was up to 79%. This is with the side panel off. After reading a bit more, that's not unusual for this card but that seems crazy hot to me. Previously, the 8800 rarely got hotter than 65C after running for several hours. (Next project: gtx 295 h2O?)

This is interesting too: at first I thought something was wrong with the clock reading, but the gtx seriously clocks itself down when idle, which is great. It goes down to 300Mhz (core) and 100 Mhz (memory).


88C isn't bad for two GTX260's ;)

As long as the temp doesn't hit 100C the card is fine. You could try a different cooler, but I don't think many of the aftermarket coolers for single slot SLI cards still vent out the back of the case.

Look here (http://www.xtremesystems.org/forums/showpost.php?p=3643941&postcount=4) for an example of an aftermarket cooler. As sweet as it looks you still gotta move air past the fins and you lose space around the card...

[bumble-bee]

Thats not right, in the first MacPro (2007) there is a 16x PCI-E slot.

The Early2008 MacPro has two of them.

No one with a 2007 MacPro in this forum who is interested in a 295 GTX??

There is no point in it, you can only have 8x (instead of 16x) speed on your GTX295.

[nanofrog]

Thats not right, in the first MacPro (2007) there is a 16x PCI-E slot.

The Early2008 MacPro has two of them.

No one with a 2007 MacPro in this forum who is interested in a 295 GTX??
There's also a utility that allows you to adjust the lane configuration in the '06 & '07 models.

Apple's changes to the '08 included a second PCIe 16x, but the lane configuration is fixed. It's caused problems for those who want, or have installed 8x lane RAID cards. (Mini SAS cables won't reach slot 2, as the custom power cable is too short).

[Maidensblush]

[QUOTE=punkmofo;7169078]Sure, I've been meaning to do that, just busy lately. I should have time this week to take some pics.


Hi Punkmofo,

can you give us some information regarding your working setup. I have exactly the same configuration as you 'Early 2008 Mac Pro 2.8 with Nvidia 8800 pre-installed. On bootcamp I have Vista 64 just like you too.

I got the card and I am trying to figure out the power scheme problem. I already have one PCIe power cord and from what I have read so far I will need to get another one supplied from the ATI website (at least for here in Canada).

Did you use the supplied 2 x 6 pin to 8 pin adapter that came with the card or did you get a third party PCIe 6 pin to 8 pin adapter cable instead to connect the 8 pin pcie connector on the GTX295?

or did you only use the one PCIe cable that came with your 8800 to power the 295 card?

For the 8800 from what I understand is that you used the optical bay Molex plug to power your 8800.

Any info would be very much appreciated,
Thanks!

Maidensblush.

[WonderSausage]

88C isn't bad for two GTX260's ;)


A GTX 295 is actually two GTX 285 cores (240 stream, 55 nm) running at the clock speed of GTX 260s for thermal management reasons.

[IEatApples]

Hey punkmofo, where's the pictures? ;)

[BRIANinDIGITAL]

In order to power the 8800gt using the molex from the optical drive, do you need a special cable or adapter to go from a molex 4 pin to a 6 or 8 pin?

[nanofrog]

In order to power the 8800gt using the molex from the optical drive, do you need a special cable or adapter to go from a molex 4 pin to a 6 or 8 pin?
Here's the cable (http://shop.ati.com/product.asp?sku=3280778) (6 pin PCIe power) from the logic board to the card.

You might be able to get away with the 4 pin Molex to 6 pin PCIe version, given the load isn't too high.

[BRIANinDIGITAL]

Here's the cable (http://shop.ati.com/product.asp?sku=3280778) (6 pin PCIe power) from the logic board to the card.

You might be able to get away with the 4 pin Molex to 6 pin PCIe version, given the load isn't too high.

Hey I was reading your posts on some other guys thread regarding the same power issue and I was a little confused with what you said. You told the guy to use 2 ati cables and a 6 to 8 pin adapter for the other 6 pin cable. That is three cables but you did not state the location of third power source. I understand the two coming from the logicboard but where does the third cable's power source come from?

[nanofrog]

Hey I was reading your posts on some other guys thread regarding the same power issue and I was a little confused with what you said. You told the guy to use 2 ati cables and a 6 to 8 pin adapter for the other 6 pin cable. That is three cables but you did not state the location of third power source. I understand the two coming from the logicboard but where does the third cable's power source come from?
IIRC, the card had a 6 pin and an 8 pin socket. So one of the ATI cables needed an adapter (6 pin to 8 pin) with it.

[BRIANinDIGITAL]

IIRC, the card had a 6 pin and an 8 pin socket. So one of the ATI cables needed an adapter (6 pin to 8 pin) with it.

Yeah I know that, but where does the other end of that cable go to? The optical drive or a y splitter? Nevermind it goes to the optical drive.

Do you need an adapter to attach it to the 4 pin molex or does it plug straight in?

[nanofrog]

Yeah I know that, but where does the other end of that cable go to? The optical drive or a y splitter? Nevermind it goes to the optical drive.

Do you need an adapter to attach it to the 4 pin molex or does it plug straight in?
The cable from ATI plugs into the logic board, then has a 6 pin end meant for the graphics card. If it's an 8 pin, an adapter cable (http://www.pcpower.com/products/description/6_to_8_Pin_PCI_E_Adapter/accessories/6-to-8-pin-adapter.html) is available.

For the 4 pin Molex to 6 pin PCIe (http://www.endpcnoise.com/cgi-bin/e/std/sku=6pin_pci_adapter), the Molex end plugs into the connector for the optical bay.

On the '09 models it would be different, as the optical bay(s) now contain SATA burners.

Perhaps this will clear things up a little. ;)

[BRIANinDIGITAL]

The cable from ATI plugs into the logic board, then has a 6 pin end meant for the graphics card. If it's an 8 pin, an adapter cable (http://www.pcpower.com/products/description/6_to_8_Pin_PCI_E_Adapter/accessories/6-to-8-pin-adapter.html) is available.

For the 4 pin Molex to 6 pin PCIe (http://www.endpcnoise.com/cgi-bin/e/std/sku=6pin_pci_adapter), the Molex end plugs into the connector for the optical bay.

On the '09 models it would be different, as the optical bay(s) now contain SATA burners.

Perhaps this will clear things up a little. ;)

Thanks Nano for your help.;)

[nanofrog]

Thanks Nano for your help.;)
:cool: I'm glad it was useful. :)

[BRIANinDIGITAL]

The cable from ATI plugs into the logic board, then has a 6 pin end meant for the graphics card. If it's an 8 pin, an adapter cable (http://www.pcpower.com/products/description/6_to_8_Pin_PCI_E_Adapter/accessories/6-to-8-pin-adapter.html) is available.

For the 4 pin Molex to 6 pin PCIe (http://www.endpcnoise.com/cgi-bin/e/std/sku=6pin_pci_adapter), the Molex end plugs into the connector for the optical bay.

On the '09 models it would be different, as the optical bay(s) now contain SATA burners.

Perhaps this will clear things up a little. ;)

Hey nano for the optical bay connection do you need to split the 4 pin molex connection in order attach both end connectors of the 6 pin power cable or do you only need to plug one of the 6 pin ends? Right now I have unplugged both optical drives to get two available 4 pin molex connections.

[BRIANinDIGITAL]

Hey nano for the optical bay connection do you need to split the 4 pin molex connection in order attach both end connectors of the 6 pin power cable or do you only need to plug one of the 6 pin ends? Right now I have unplugged both optical drives to get two available 4 pin molex connections.

Nevermind. I tried it with just one connection.

[10THzMac]

Nevermind. I tried it with just one connection.

And did it work - I finally yanked out the optical drive cage and just found one molex as you note - is it in fact enough just to connect this? Does the card (which one) run OK without strange things happening.

Meantime I was cursing Apple for the case design - how have you routed the cable given that there is a plate and a drive bay blocking the most obvious route?

Edited - never mind - got it working with just one molex after grabbing an adaptor from PCWorld. Very pleased - thanks for this. Now have my Mac Pro case closed with the 8800 off the spare optical molex and the 285 off the two motherboard connectors. I still have no idea whether there is any way of powering a 295 internally, or if my latest power setup would still run if I had two opticals. I can only just get the cable routed though - quite why Apple needed to put a plate between the optical area and the cards area is a mystery.

[diamond.g]

A GTX 295 is actually two GTX 285 cores (240 stream, 55 nm) running at the clock speed of GTX 260s for thermal management reasons.
Hmm, interesting. It looks like it could be the 285 with lower clock and mem speeds. At the time it made more sense for it to be a golden sample 260 with all the sp's unlocked. But the 285 core would make more sense.