Gaming graphics in Mac Pro 3,1

[ActionableMango]

Originally Posted by MacVidCards

The real sp[eculation should be on future of 2013 Mac Pro. Do they switch to GOP and make all prior cards unusable, and thus new cards unusable on previous Mac Pros or do they continue using their pre-release EFI that no longer complies with UEFI as implemented by WIndows world?

Bit of a conundrum, actually.

Can they just have a larger ROM and include both, or are they mutually exclusive?

As I understand it there are already two boot methods in the ROM: BIOS and EFI. Why not three?

[BDM STUDIOS NL]

[QUOTE=DanielCoffey;16745486]Killerbob - I would advise only having a single graphics card in the machine at one time. It avoids driver conflicts, power issues and noise.

NOT TRUE!!! My setup works flawless with the original GT8800 MAC and the ATI 2600HD in combination with the EVGA GTX 670 FTW 2 and 4GB versions, the latter doesn't extra power (45w)!

No driver issues, even with the combined ATI and EVGA Nvidia cards
No power issues
No noise issues more then normal when using high GPU loads! That's what the fans are made for!

[Pithism]

i have the NVIDIA GT8800 MAC-EDITION and a EVGA GTX 660. I have tried to connect both. I have the EVGA in slot 1 and NVIDIA GT8800 MAC-EDITION in slot 2. I bought another apple PCIe connector, just like the stock one, and have connect both of them to the board but they wont work in tandem.

Both combined dont exceed 300w, but they never work when plugged into the motherboard at the same time. Do you have any idea or thoughts on how to make them both work at the same time.

Does it have to do with drivers? i have the nvidia drivers installed. would using the Apple Mini-PCIe 6-Pin to Standard Dual PCIe 6-Pin Video Card Power Cable make it work? I would think using 2 cables would work fine, but its not.

I would really like to have the option of going to recovery if something bad happens, and not switch out GPU's.


My mac is 3,1 2008 model.

Any help would be awesome by anyone.

[BDM STUDIOS NL]

Originally Posted by Pithism

i have the NVIDIA GT8800 MAC-EDITION and a EVGA GTX 660. I have tried to connect both. I have the EVGA in slot 1 and NVIDIA GT8800 MAC-EDITION in slot 2. I bought another apple PCIe connector, just like the stock one, and have connect both of them to the board but they wont work in tandem.

Both combined dont exceed 300w, but they never work when plugged into the motherboard at the same time. Do you have any idea or thoughts on how to make them both work at the same time.

Does it have to do with drivers? i have the nvidia drivers installed. would using the Apple Mini-PCIe 6-Pin to Standard Dual PCIe 6-Pin Video Card Power Cable make it work? I would think using 2 cables would work fine, but its not.

I would really like to have the option of going to recovery if something bad happens, and not switch out GPU's.


My mac is 3,1 2008 model.

Any help would be awesome by anyone.

What do you see when powering the the MAC with both cards installed AND do you use TWO monitors? The GTX 660 WILL NOT show you your initial Apple bootscreen. SO hook the 8800GT MAC to i.e. to a small system monitor. I have a very old 19" hooked to my 8800GT.



Does the GTX 660 has 2 power connectors on the card itself? If so it needs a dual power line as shown in my earlier post in this thread! Make sure to CROSSlink the two Y-spit cables t both graphics cards!


My hardware setup in Mac Pro 3.1

EVGA installed in Slot-1, NVIDIA MAC installed in Slot-2

NVIDIA GT8800:
1x PCIe 6-pin from onboard connector #1

EVGA GTX 670 4GB FTW:
1x PCIe 6-pin from onboard connector #1
1x PCIe 6-pin from onboard connector #2

1x PCIe 6-pin from onboard connector #2 = SPARE

[Killerbob]

I can't find the references, but there has been mentionings in forums that splitting the 6-pin power cables in the Mac Pro is a VERY bad idea. Supposedly this setup can draw too much power and fry the motherboard.

I know it probably works in many cases, even for longer time, but one day you might try to turn on the MP and find it rendered useless. Your call...

[BDM STUDIOS NL]

Originally Posted by Killerbob

I can't find the references, but there has been mentionings in forums that splitting the 6-pin power cables in the Mac Pro is a VERY bad idea. Supposedly this setup can draw too much power and fry the motherboard.

I know it probably works in many cases, even for longer time, but one day you might try to turn on the MP and find it rendered useless. Your call...

Please share links to the threads you mention, so we can all check that!
Much appreciated!

[Killerbob]

As I said, I can't find the references, but effectively you are demanding more than the standard 75W from each power cable. Just because you are only running/using one of the cards, the other is still running, i.e. pulling power.

Each card will pull power from the PCIe slot, that's OK, the Mac Pro can handle it.

Each card will however also pull power from the PCIe power cables, and they are only dimensioned to handle 75W. In your example you are possibly pulling 2x75W from onboard connector #1 if I understand it correctly. Again, the Mac Pro can handle it, the PSU is rated at 980W However, the connector on the MoBo can't, and there is a likely possibility that one day it will die!

It is the same as using the 6-pin MoBo connector in an 8-pin card (using a splitter or not) - i.e. HIGHLY DISCOURAGED. It may work fine for a while, but you do risk the chance of frying your MoBo or graphics card. You can read page up and page down about this in these forums - ASGORATH is a great source for this.

I am not saying it does not work, I know BDM has been doing this for a long time, I am merely saying it is very much at your own risk, and shouldn't be encouraged.

[BDM STUDIOS NL]

Hi Bob,

Even after a lot of time spending on forums before my excecution of the Y-splitting and crosslinking the power to both cards, I'll submit a post on apple.com just to check for comments from some of the guru's there! 😎

Thanks for your extensive reply on this matter!

Keep you posted! Cheers

[Pithism]

Originally Posted by BDM STUDIOS NL

What do you see when powering the the MAC with both cards installed AND do you use TWO monitors? The GTX 660 WILL NOT show you your initial Apple bootscreen. SO hook the 8800GT MAC to i.e. to a small system monitor. I have a very old 19" hooked to my 8800GT.

Image

Does the GTX 660 has 2 power connectors on the card itself? If so it needs a dual power line as shown in my earlier post in this thread! Make sure to CROSSlink the two Y-spit cables t both graphics cards!


My hardware setup in Mac Pro 3.1

EVGA installed in Slot-1, NVIDIA MAC installed in Slot-2

NVIDIA GT8800:
1x PCIe 6-pin from onboard connector #1

EVGA GTX 670 4GB FTW:
1x PCIe 6-pin from onboard connector #1
1x PCIe 6-pin from onboard connector #2

1x PCIe 6-pin from onboard connector #2 = SPARE

Well my problem is that it wouldn't even boot, but each one would boot when the other wasn't connected in the pci slot. I booted once with both powered successfully, but since then no luck.

And i do know that my evga isn't able to show bootscreen, which is why i want to get the old nvidia card to work.

I do have two newer montiors, one is from 2009 (asus)and the other is 2011 (samsung), so maybe the monitors are drawing to much power? I doubt it but who knows.

The GTX 660 only has 1 power connector by the way.

I had tried connecting both cards in different connector ports, so the evga in 1 and 2 as well as the old GT card. No luck.

Any other idea besides trying a old monitor?

[Killerbob]

Originally Posted by Pithism

I do have two newer montiors, one is from 2009 (asus)and the other is 2011 (samsung), so maybe the monitors are drawing to much power? I doubt it but who knows.

Your monitors do not draw power from the computer...

If your two graphics cards both only have one 6-pin power connector, and you have connected both of the MoBo PCIe power cables to each their own connector on the MoBo, there should be no reason why it does not work.

You could try switching around the power cables, to check if one of them is a dud, and you have already tested the cards, and the two slots, so try the different combinations, and see if that won't narrow down the culprit.

[Pithism]

Originally Posted by Killerbob

Your monitors do not draw power from the computer...

If your two graphics cards both only have one 6-pin power connector, and you have connected both of the MoBo PCIe power cables to each their own connector on the MoBo, there should be no reason why it does not work.

You could try switching around the power cables, to check if one of them is a dud, and you have already tested the cards, and the two slots, so try the different combinations, and see if that won't narrow down the culprit.

ok ill try that same stuff again. Both cables work fine. both power connectors work fine, ill figure it out. thanks for the help. Just good to know that i should work. Ill work around with the cables and cards and power connectors etc.

[Pithism]

got both to work finally thanks.