Two GeForce 9800 GX2's in a Mac Pro with an external power supply

[adrianofmaia]

So, I think that even tough the performance increase is very nice. I am almost sure that those numbers are using only one core of the 9800gx2 on OSX.

On Vista64 the performance increase is much much noticeable. Which make me believe that under windows it is using both cores. That, or OSX OpenGL implementation is just crap.

[zmttoxics]

Very cool experiment, but for me the cost is way too great. My gaming box is a kick ass machine for sure, but cost way under that of a mac pro and got me the same results. Not to put down the Pro at all (I think its awesome for sure), but I just can't justify the cost at that point.

Nice work though!

[ildondeigiocchi]

I believe the starter of this post deserves a lot of respect for what he has done. Trying something where the odds were against him and succeeding. He is among the very few who has actually tried and accomplished something remarkable with graphics cards and MAC OSX.

[ceres]

Definitely right to point out that the MP has some rather glaring weaknesses.
Also commendable that somebody is going to great lengths to alleviate the situation. It´s certainly not very economic in any way but points out that a true workstation needs to offer more choice of vga cards.
As always some acolyte jumping in to second the Appleknowsitbest sermon.

In January the 4870 should be availabe for MP and as there isn´t something better on AMDs roadmap right now we should be fine

[Consultant]

hey adrianofmaia,

It's incredible that you got it to work. People should write to:
apple.com/feedback

[adrianofmaia]

After some more tests, I got to some conclusions:

1. Under OSX, it will only use one 9800gx2 core. You can still use both cores for CUDA application and all that stuff that doesnt require SLI to use both cores.

2. Under Vista64, it is possible to put the 9800gx2 (single card) in SLI. Making use of both cores of the card. Instructions bellow.


How to make 9800gx2 (single card) SLI works under Vista64 on a Mac PRO.

In my case I had to connect one display on each video card. One display on the DVI-2 port of the 8800gt and one on the DVI-1 of the 9800gx2. Plug the monitor that you want to be your main display on DVI-1 of the 9800gx2.

1. Make sure you have the latest drivers for windows installed, and that both cards (8800gt and 9800gx2) are working under vista64. Se my past posts if you want to know how.
2. Go to control panel and open the display configuration (I don't recall the exact names). On the display configuration panel, make the display on the 9800gx2 your main desktop, and disable the display that is connected to the 8800gt (disable "extend my desktop" also).
3. Right now if you try to go to the nvidia control panel to enagle SLI, you wont be able to. Do the next step.
4. Go to the Device Manager option, under ControPanel/System. Then go to Display Adapters. You should see one 8800gt and two 9800gx2 (each core is recognized as one card).
5. Right click on the 8800gt, and click disable.
6. Now go to the nVidia control panel, and enagle SLI for your 9800gx2 (option should be available now). If the nvidia panel asks to close application and stuff, just click " yes" for everything.
7. Your screen will go blank and windows will make the 8800gt your display again (using framebuffer at 640x480). Don't panic. Nvidia control panel will looks like it is freezed. Don't worry. Just Accept everything the system asks you and then reboot your computer.
8. Login on windows again.
9. Go to the Device Manager again.
10. Go to the Display Adapters list, under System. Right click the 8800gt and hit "Enable".
11. Reboot your computer.

Now you should have both cards working again and the 9800gx2 will be in SLI. Make the 9800gx2 your default display again. You can now use the 8800gt to extend your desktop if you wish.

To make sure that SLI is really enable and working, use this tool here:
http://www.nhancer.com/

It will show you a green "SLI Enabled". And allows you to enable SLI load bars. So you will see in game one green bar showing the GPU usage for both cores.

Sorry for the quick and dirt explanation. Just don't have time right now to do something more elaboreted.

Have fun.

[yaysprinkledirt]

Is an external power supply absolutely necesary to get the 9800 gx2 working with an 8800gt?

[adrianofmaia]

The Mac Pro PSU has enough power for both (depending if you use all 4 HD bays or not). But you would have to make/buy some adapters to drain power from the cables hidden in the DVD-driver bays. I was too lazy for that.

[blackrnnero]

hi
could you help me?
any ideea if 9800gx2 in osx boost the render of core image?
i have a project that use a lot of colorisation. Apple Color uses the GPU for rendering. I switched my 2600xt with a 8800gt and the render is slower.
I don't know if a Core Image Benchmarck exists.
Thanx in advance,
Cosmin

[The Rominator]

Exciting progress !!

I am trying to get a 9800GTX going in my Mac Pro and this is all quite interesting.

Things I think I figured out so far:

1. The EFI portion of ROM may contain initial boot settings but the actual card speeds, RAM timing etc come from the good old PC Bios. Up the clocks on a card with Nibitor and reflash and it runs faster/slower in OSX.

2. The EFI device id and PC BIOS Device id need to match. In addition, the PC BIOS uses softstraps to code the device id from a range of possibilities. Modding the easy to see device ids but NOT changing the one coded into straps results in NADA.

3. Card name comes from PC BIOS for Apple System Profiler. However, OpenGL View gets card name by comparing device id to a list.

4. Any mods made to ROM must be opened and saved in Nibitor to maintain PC checksum.

5. So, at boot the EFI is loaded and card fires up. The real work is done from PC BIOS. So.....

Does the EFI have a roadmap in it to where the needed values are in the PC BIOS? Or does it load on it's own separately and drop values in various registers?

The reason I post this question...what if the 9800GX2 BIOS could be joined with the EFI BIOS in such a way that it could boot without the 8800GT in there?

I just tried the 9800GTX with a 8800GT in machine. GTX in slot 2. It was id'd in OSX as "G92 Board 0392xxx" and listed two display ports but would not detect displays attached there. I tried with and without SLi cable on. Guess I should try switching slots. Also, I need to add a second power source...just had one cable for GTX.

On another thought..did anyone pry open the kexts on Snow Leopard and see if the device id's for additional cards are in there?

[trainguy77]

Originally Posted by The Rominator

Exciting progress !!

I am trying to get a 9800GTX going in my Mac Pro and this is all quite interesting.

Things I think I figured out so far:

1. The EFI portion of ROM may contain initial boot settings but the actual card speeds, RAM timing etc come from the good old PC Bios. Up the clocks on a card with Nibitor and reflash and it runs faster/slower in OSX.

2. The EFI device id and PC BIOS Device id need to match. In addition, the PC BIOS uses softstraps to code the device id from a range of possibilities. Modding the easy to see device ids but NOT changing the one coded into straps results in NADA.

3. Card name comes from PC BIOS for Apple System Profiler. However, OpenGL View gets card name by comparing device id to a list.

4. Any mods made to ROM must be opened and saved in Nibitor to maintain PC checksum.

5. So, at boot the EFI is loaded and card fires up. The real work is done from PC BIOS. So.....

Does the EFI have a roadmap in it to where the needed values are in the PC BIOS? Or does it load on it's own separately and drop values in various registers?

The reason I post this question...what if the 9800GX2 BIOS could be joined with the EFI BIOS in such a way that it could boot without the 8800GT in there?

I just tried the 9800GTX with a 8800GT in machine. GTX in slot 2. It was id'd in OSX as "G92 Board 0392xxx" and listed two display ports but would not detect displays attached there. I tried with and without SLi cable on. Guess I should try switching slots. Also, I need to add a second power source...just had one cable for GTX.

On another thought..did anyone pry open the kexts on Snow Leopard and see if the device id's for additional cards are in there?

I don't think that would be true because when the intel macs first came out they system didn't have a bios on it. BootCamp and the firmware update came after intel macs. So back before they had a bios emulator what would be the point of using the bios side of the cards? If the bios side even existed back then that is.

[The Rominator]

And yet this guys card is working....there is now way a 9800GX2 is running on a EFI BIOS for 8800GT.

So...it has used the EFI to validate, then run on the PC BIOS.

Don't know any other way to interpret this.

If the EFI BIOS was only thing providing info on card it would show up as 8800GT and run as one.

Experimentation beats postulation every day.

[trainguy77]

Originally Posted by The Rominator

And yet this guys card is working....there is now way a 9800GX2 is running on a EFI BIOS for 8800GT.

So...it has used the EFI to validate, then run on the PC BIOS.

Don't know any other way to interpret this.

If the EFI BIOS was only thing providing info on card it would show up as 8800GT and run as one.

Experimentation beats postulation every day.

But the ones without the EFI part can't show the boot screens.
Also they need extra drivers to run, so those drivers could make it pull the data from the bios. VS a OEM card's drivers might pull the data from EFI.

I am not arguing i am just throwing other ideas out their.

[kahine]

Originally Posted by blackrnnero

hi
could you help me?
any ideea if 9800gx2 in osx boost the render of core image?
i have a project that use a lot of colorisation. Apple Color uses the GPU for rendering. I switched my 2600xt with a 8800gt and the render is slower.
I don't know if a Core Image Benchmarck exists.
Thanx in advance,
Cosmin

It's because ATI cards do Core much better than Nvidia , a 3870 is what you want if anything

That 2600xt beats the 8800gt because of that

[pwn247]

I've read through this topic over the past half an hour, and I'm extremely interested to try this. My 2006 Mac Pro (specs in signature) has an outdated 7300GT, which is unacceptable for what I paid for her- in 2008.

I wish Apple didn't make it so damned hard to get a PC GPU working in a system that most power users could only dream of having. A high end system needs to be expandable to all types of hardware- PC or Mac.

So now that I'm done ranting, I've actually been looking into buying a 9800GTX and using it in my Mac Pro for Windows (I don't need it for OS X). I've heard that with my model (the 1,1 or 2006 model), you have to pop open the case and swap on the video card each time you switch between Windows and OS X; is this true? Or can I leave the 7300 [] in there with the 9800 [PC]?

Also, I don't really want to have an external PSU to monkey with, so does anyone have pictures of how they routed a power cable down from the optical drive bays where the Mac Pro PSU is at?

[deniesun]

hi, adrianofmaia,
you really deserve a big congratulation on this topic and for the effort through it. i have an early 2008 mp with octacore 2.8 and 6gb of ram and recently got my two 8800gt upgrade kits. since you have succeeded to work 9800 gx2 in sli mode on vista x64, i'm certain that you could tell me how to use my cards in sli mode in vista x64 on bootcamp. i'm using the latest forceware drivers (181.00), but i don't get the "enable sli" check box whatsoever on my control panel no matter which driver i use even the modded 169.00 driver. i will appreciateany kind of help.

[ildondeigiocchi]

Originally Posted by deniesun

hi, adrianofmaia,
you really deserve a big congratulation on this topic and for the effort through it. i have an early 2008 mp with octacore 2.8 and 6gb of ram and recently got my two 8800gt upgrade kits. since you have succeeded to work 9800 gx2 in sli mode on vista x64, i'm certain that you could tell me how to use my cards in sli mode in vista x64 on bootcamp. i'm using the latest forceware drivers (181.00), but i don't get the "enable sli" check box whatsoever on my control panel no matter which driver i use even the modded 169.00 driver. i will appreciateany kind of help.

You will never get SLI to work with two 8800GT's. The only Intel motherboard which does support SLI is the X58. The 9800GX2 got SLI working because it's technically 2cards in one i.e. almost like an automatic SLI but adrianofmaia was able to get quad SLI working with both cards which further proves the Mac Pro motherboard is not SLI capable. Only one of your 8800GT's will work unless you are able to perform some Godly miracle. Good luck:P

[deniesun]

Originally Posted by ildondeigiocchi

You will never get SLI to work with two 8800GT's. The only Intel motherboard which does support SLI is the X58. The 9800GX2 got SLI working because it's technically 2cards in one i.e. almost like an automatic SLI but adrianofmaia was able to get quad SLI working with both cards which further proves the Mac Pro motherboard is not SLI capable. Only one of your 8800GT's will work unless you are able to perform some Godly miracle. Good luck:P

thank you for the explanation, maybe i misunderstood what adrianofmaia did ,since i know almost nothing about sli configuration, somehow i thought he did sli on two cards; one 8800gt an one 9800gx2. so you say the reason why he sees the option check box that says "enable sli" on his control panel is, even two gpu's on a single card needs to be "sli"ed, therefore only thing he did was to introduce those two gpu's to the system as one gpu with the power of two.
correct me if i'm wrong.

[adrianofmaia]

hello deniesun,

You are correct. In fact I only enabled the SLI to use the full power of one 9800gx2 (two cores). There are rumors of people that hacked their drivers and forced two single-core cards to work in SLI. But those same people never posted proof or any piece of information that allowed people to reproduce what they did, so...

I had to use the 8800gt just to make its efi-firmware "boot" both cards (8800 and 9800) to macos. Which I think it's dumb and proves that non-efi video cards would work just fine in macos-x, if apple wish so (aka wanted to be nice with their costumers that just payed a **** ton of money for a "top end MacPro").

As for me, this experience at least made possible that I could use a better video card on my macpro (other than an old 8800gt. which is a very-very-very old card to use on the 2008 macpro). I am planning to upgrade my system early in 2009 (my 2008-mp still has *a lot* of unused processor power, but the 9800gx2 is already old for me. and I can't upgrade it.) and as much as I would like to stay with a bad-ass (poor supported) macpro, I will sell it and just buy a much superior PC with about half the money.

[deniesun]

Originally Posted by adrianofmaia

hello deniesun,

You are correct. In fact I only enabled the SLI to use the full power of one 9800gx2 (two cores). There are rumors of people that hacked their drivers and forced two single-core cards to work in SLI. But those same people never posted proof or any piece of information that allowed people to reproduce what they did, so...

I had to use the 8800gt just to make its efi-firmware "boot" both cards (8800 and 9800) to macos. Which I think it's dumb and proves that non-efi video cards would work just fine in macos-x, if apple wish so (aka wanted to be nice with their costumers that just payed a **** ton of money for a "top end MacPro").

As for me, this experience at least made possible that I could use a better video card on my macpro (other than an old 8800gt. which is a very-very-very old card to use on the 2008 macpro). I am planning to upgrade my system early in 2009 (my 2008-mp still has *a lot* of unused processor power, but the 9800gx2 is already old for me. and I can't upgrade it.) and as much as I would like to stay with a bad-ass (poor supported) macpro, I will sell it and just buy a much superior PC with about half the money.

hi adrianofmaia,
thank you for the reply. it seems my second 8800 gt is useless at the moment, unless i want to use a secondary display ( which i don't intend to ). so i will get rid of it and look forward to your new experiments. i am not a heavy gamer but a various 3d software user who works with quite heavy 3d scenes which are allways hungry for extra power on the gpu. rumors are there will be support for ati 4870 soon. my hope is early 2008 mp's will not be excluded and may be you will find a way to work non-efi regular/modded two 4870x2 in cf mode which doubles the power of strongest quadro or fire gl for quarter the price of them.

[macintouch]

Much respect and admiration to adrianofmania. I applaud your work and experimentation. It's nice to see that people are playing around and experimenting. There's lots of trash talkers, not a lot of doers! Cheers.

[deniesun]

ok, i'm getting rid of my second 8800 gt now and will have a 9800gx2 instead and follow the instructions. but i have another question; is it possible to soft mod that "efi"ed and "sli"ed 9800gx2 into quadro fx 4700x2 since they are based on the same g92 chipset and everything?

[10THzMac]

Could adrianofmania summarize exactly what he had to do to get CUDA recognizing all the cards under OS X? My GTX 285 is sitting next to a 8800GT that is used to boot and deviceQuery only reveals the 8800GT under CUDA 2.1 Mac. Both are seen under CUDA under Windows. It is very tantalizing to see all those boards up under OS X and I have to wonder if I am a small step away from using CUDA on both under OS X?! Or maybe the GTX 200 architecture is too different.

It would help if someone could explain how to edit a kext file, for a start!