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

O

otsego

macrumors newbie
Original poster
Apr 4, 2008
2
0
I just came over an idea. What if I order a Corsair 750W power supply that carries two 8-pin PCIe connectors (where a 6-pin cable can be connected). I then proceed to order two GeForce 9800 GX2 cards and put them in a Mac Pro. I then hook up the Corsair power supply to the two cards (notice I will have the side door removed for this set-up), as well as a U-shaped paper clip (as according to Corsair's own "how to test your power supply manual) to make the 24-pin ATX cable provide power, thus powering up the power supply and delivering power to the two cards. This way you can have two GeForce 9800 GX2 cards in your Mac Pro, or at least so I believe.

Before I go ahead and zap my Mac Pro, purchase two 9800 GX2's I can't use, or somehow reverse the electricity and blow up my house, does anyone have any more information regarding this? Two heads (or 20 for that matter) can think more than one, and probably spot something I didn't think of.
 
otsego said:
I just came over an idea. What if I order a Corsair 750W power supply that carries two 8-pin PCIe connectors (where a 6-pin cable can be connected). I then proceed to order two GeForce 9800 GX2 cards and put them in a Mac Pro. I then hook up the Corsair power supply to the two cards (notice I will have the side door removed for this set-up), as well as a U-shaped paper clip (as according to Corsair's own "how to test your power supply manual) to make the 24-pin ATX cable provide power, thus powering up the power supply and delivering power to the two cards. This way you can have two GeForce 9800 GX2 cards in your Mac Pro, or at least so I believe.

Before I go ahead and zap my Mac Pro, purchase two 9800 GX2's I can't use, or somehow reverse the electricity and blow up my house, does anyone have any more information regarding this? Two heads (or 20 for that matter) can think more than one, and probably spot something I didn't think of.
Click to expand...

Good luck, but I doubt you will be happy with this setup ... what is your plan with the two cards ... driving two dispays???
 
Thank you SuperGrobi, I will probably need all the luck I can while explaining to the Fire Marshall what on earth happened. Seriously though ;) The main reason why I'm doing this is because I can. I like to make things do stuff they never were supposed to in the first place. It's a fun project and I'll probably get some others to jump in on this set-up, and then make fun of the Windows hippies complaining you can't run anything on a Mac ;)

(Yes, I am aware I will need to run Windows for this set-up to work, but it will nevertheless still be a Mac)
 
I would already be happy if I was able to run just one 9800GX2 in Vista without having to pull it out when I want to boot Mac OS. I don´t think this is just a power issue ... I am waiting for a genius who is able to modify a 8800GT ROM to run a 9800GX2 in Mac OS (I wouldn't mind if that would mean that the card just runs on one GPU then) ... but, I doubt that will ever happen. Might be that the 8800GT will be the top end card for Mac OS in the next 1 or more years. I have more hopes that one can make a 9800GTX run in Mac OS. Two 9800GX2 would only be interesting for me if there is the slightest chance to run them in SLI, but for that I´ll probably rather buy a gaming PC with an nForce 3-way SLI mainboard ;)
 
Mac Pro can not SLI that.



There is one report of a successful SLI of 7600's with hacked firmware, but it was impossible for 8800 and since 9800 is the same model only twice the memory, it will not work. 9800 is crappy overall and has been reported to have same stats as a overclocked 8800GTS. If you wanted to game why get a Mac?
 
It seems like a rather silly thing to do, bearing in mind the kludging (or to unkludge it, a lot of work) involved.

I have Pros at home, but I have a separate Skulltrail-based system that arrived a couple of days ago to run the dual 9800GX2's. Why not do it properly? :confused:
 
I was under the impression the real issue was that the PCI-E slots have a maximum power wattage allotted to them... that the PSU rating makes no difference. Am I missing something?

brand said:
Real Macs run OS X.
Click to expand...

Real Macs use a PowerPC (or a 68K) processor... and if they run a Unix-based system, also run OS 9.2.2 or earlier. =)
 
The Mac Pro does not support SLI. I already tried it with two 8800 GTS cards. It sees them as two separate cards even with the SLI bridge attached. If the motherboard was SLI "aware," the nVidia control panel would let you enable or disable SLI mode.

My Radeon HD 3870 X2 pulls over 200 watts under load. HardOCP claims the 9800 GX2 pulls even more. Even if you power the second 9800 GX2 externally from a stand alone power supply, you're going to be exceeding the 300 watt limit of the PCie bus. I'd be afraid of burning up your machine.

I suggest you stick to one 9800 GX2.
 
barefeats said:
The Mac Pro does not support SLI. I already tried it with two 8800 GTS cards. It sees them as two separate cards even with the SLI bridge attached. If the motherboard was SLI "aware," the nVidia control panel would let you enable or disable SLI mode.

My Radeon HD 3870 X2 pulls over 200 watts under load. HardOCP claims the 9800 GX2 pulls even more. Even if you power the second 9800 GX2 externally from a stand alone power supply, you're going to be exceeding the 300 watt limit of the PCie bus. I'd be afraid of burning up your machine.

I suggest you stick to one 9800 GX2.
Click to expand...

Hah, I forgot it didn't even support SLI! Duh. How could it. Not exactly an nForce chipset is it? =\
 
barefeats said:
The Mac Pro does not support SLI. I already tried it with two 8800 GTS cards. It sees them as two separate cards even with the SLI bridge attached. If the motherboard was SLI "aware," the nVidia control panel would let you enable or disable SLI mode.

My Radeon HD 3870 X2 pulls over 200 watts under load. HardOCP claims the 9800 GX2 pulls even more. Even if you power the second 9800 GX2 externally from a stand alone power supply, you're going to be exceeding the 300 watt limit of the PCie bus. I'd be afraid of burning up your machine.

I suggest you stick to one 9800 GX2.
Click to expand...

1. The GX2 is a single card so should work as SLi. It does in Intel Mobo PCs so it should in a Mac Pro in Windows.

2. No it doesn't. The limit of draw from a PCI-E 1.1 slot is 75W IIRC and PCI-E 2 is 90-100W. 72+ 75 = 150W, well within the limits. The rest of the power is taken from the external leads.

Two GX2s however is pointless.
 
I tryed :)

I don't know if the original poster did. But I tried :) .

Long history:

Today I was trying to get 2x nVidia 9800 gx2 to work on vista64 on my MacPro (early 2008 with 2x2.8quad).

Everybody knows that for the mac pro even turn on (and actually do the chime), you need an EFI-capable video card pluged in inside your mac.

First I tryed with the original ATI 2600 card + the two 9800gx2. With that setup, I could boot into windows, but since the primary monitor always is recognized on the ati, since thats the one EFI-enabled, I could never get the nvidia drivers to load on windows. I guess you can't have ati and nvidia drivers loaded at the same time.

Ok. Based on the few things that I could conclude, I decided to get the apple upgrade kit (with one 8800 GT, EFI-enabled). With that I could try to load windows and get nvidia drivers loaded. However, for some wierd reason, after I hold down "option key" and select the boot camp partition, the mac insta-freeze.

I was tired of try to get vista64 to work. I will keep trying tomorrow. However, before I shutdown everything, I decided to boot on my MacOSX 10.5.5 partition with the 3x nvidias pluged (2x 9800gx2 and one 8800gt from the apple upgrade kit).

If you try to boot MacOS X with the 9800gx2 and any other card, you will see that MacOS will not even detect the 9800gx2, because there is no EFI on the 9800 firmware. But look what happens when you boot with the 9800gx2 and the 8800gt (EFI enabled).

8800gt.png

9800gx2s1.png

9800gx2s2.png


That was without the SLI cable connecting the two 9800gx2.

If I connect the SLI cable, putting the two 9800gx2 in SLI, I get this on MacOS:

withsli.png


If you take a look on the screenshots, on the 9800gx2 it shows the Rom Revision as 3233. In fact, thats the EFI of the 8800gt, that for some reason MacOS also used for the two non-EFI 9800gx2 cards.

I am no driver expert. But my guess is: now that we actually know how to make MacOS "see" the two 9800gx2 as valid cards, if we could make him associate that card with a working driver, we could make those 9800 work on MacOSX (running on a real mac, not hackintosh).

For those who are curious about how I managed to actually power the two 9800gx2 and one 8800gt inside a MacPRO, I just used an additional external power supply. Here are the pics:

externalpsu.jpg

cards.jpg

sli.jpg


If anyone can help me on that, please feel free to ask any additional information.

Also, does anybody has any clue about why my MacPRO just freezes when I choose the bootcamp partition? (with the 3 nvidia cards inside, it will boot and load windows no problem if I plugin the ATI2600 plus the two 9800gx2 together.) It freezes right away, with the disk boot selection screen. It doesnt even turn the screen black to boot windows.
 
After some reading, I saw that little to no applications/games benefits from quad-sli (with two 9800gx2). So i decided to screw with the two 9800gx2 and stick just one 9800gx2 and one 8800gt( so I could boot OSX).

As soon as I removed the 9800gx2 that was on Slot-1 and transfered the 8800gt from Slot-4 to Slot-1. And left the other 9800gx2 on the Slot-2. I could finally boot on my boot-camp partition. I guess the double GX2 setup was making vista64 boot go crazy.

However, vista64+macpro+9800gx2 is no news.

Let's talk about the MacOS side.

I learned from windows that, when you power on your MacPRO, the 9800gx2 fans go crazy, full power. But as soon as the windows driver loaded, the fan goes into a quite mode. You can barely hear the fan, unless it gets too hot.

Well, when I tried to boot MacOSX with ATI2600 + 9800gx2, the gx2 stayed with fans at full speed all the time. MacOS would never recognize the 9800gx2, only the ATI2600.

But when I tried to boot with the 8800gt on SLOT-1 and 9800gx2 on SLOT-2, as soon as the apple disappeared and the blue screen appeared, the 9800gx2 went into a quite mode (fan at lower speeds, drivers probably reconegnized the card). And OSX got stuck on that blue screen right before the login screen. The machine was not frozen. I could turn caps lock on and off. But Never got past that screen. My guess is, when I boot in OSX with 8800gt+9800gx2, the 8800 EFI makes OSX recongnize the 9800gx as a legit card also and tries to load the drivers.

Will keep you all posted.
 
As I suspected, the system was not frozen. Just stuck on that blue-ish screen before the login screen. But I could login via SSH. And as i suspected, OSX indeed recognized the video card. My CUDA-enable nVidia driver even saw the 9800gx2 as a CUDE device.

Code: 
$ ./deviceQuery
There are 3 devices supporting CUDA

Device 0: "GeForce 8800 GT"
Major revision number: 1
Minor revision number: 1
Total amount of global memory: 536674304 bytes
Number of multiprocessors: 14
Number of cores: 112
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 16384 bytes
Total number of registers available per block: 8192
Warp size: 32
Maximum number of threads per block: 512
Maximum sizes of each dimension of a block: 512 x 512 x 64
Maximum sizes of each dimension of a grid: 65535 x 65535 x 1
Maximum memory pitch: 262144 bytes
Texture alignment: 256 bytes
Clock rate: 0.60 GHz
Concurrent copy and execution: Yes

Device 1: "G92-450"
Major revision number: 1
Minor revision number: 1
Total amount of global memory: 536674304 bytes
Number of multiprocessors: 16
Number of cores: 128
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 16384 bytes
Total number of registers available per block: 8192
Warp size: 32
Maximum number of threads per block: 512
Maximum sizes of each dimension of a block: 512 x 512 x 64
Maximum sizes of each dimension of a grid: 65535 x 65535 x 1
Maximum memory pitch: 262144 bytes
Texture alignment: 256 bytes
Clock rate: 1.51 GHz
Concurrent copy and execution: Yes

Device 2: "Device Emulation (CPU)"
Major revision number: 1
Minor revision number: 1
Total amount of global memory: 536674304 bytes
Number of multiprocessors: 16
Number of cores: 128
Total amount of constant memory: 65536 bytes
Total amount of shared memory per block: 16384 bytes
Total number of registers available per block: 8192
Warp size: 32
Maximum number of threads per block: 512
Maximum sizes of each dimension of a block: 512 x 512 x 64
Maximum sizes of each dimension of a grid: 65535 x 65535 x 1
Maximum memory pitch: 262144 bytes
Texture alignment: 256 bytes
Clock rate: 0.00 GHz
Concurrent copy and execution: Yes

Test PASSED

Press ENTER to exit...

Look at that. the G92 devide was recognized with 1.51Ghz Clock rate, which is indeed the 9800gx2 clock.

My guess is, that after load the 9800gx2 device, OSX tried to switch the default display to that card. I will do some more testing. Will connect one display on each of the 9800gx2 outputs, even the HDMI one, and see if I get any signal.

./crossfingers
 
Checking system.log via SSH I got this:

Code: 
Sep 19 22:24:47 localhost kernel[0]: NVDA::probe(display)
Sep 19 22:24:47 localhost kernel[0]: NVDA::start(display) <1>
Sep 19 22:24:47 localhost kernel[0]: NVDA::start(display) <1> failed

So yeah. After the boot (apple with gray screen) it tries to send the signal to display <1> and it fails. Thats why I don't get the login screen. everything else starts ok, I can access the system via SSH.

My guesses are:

1. The system recognizes everything, including my 9800gx2, but when it tries to send display signal to display<1> it fails. And since I tryed to boot with a DVI monitor connected to both DVI ports on the 9800gx2, I think the display<1> is the HDMI port. My ****ing TV is too far away from my macpro right now. I guess i will have to bring it closer (and unplug all the billion cables connected to it. My wife will kill me.)

or

2. The system recognizes everything, including my 9800gx2 (because of the 8800gt EFI-bios). However, the EFI is not 9800gx2 compatible and thats why OSX can't send the display signal thought the 9800gx2 card. Which I doubt it's true. Because I read somewhere that once the system see that EFI is up, it wont even use anything from the EFI firmware, it will load the actual drivers (kext) and go from there. And also, I can use CUDA-applications via command line (ssh). So I am actually been able to access the 9800gx2 no problem.

I will do two more tests now. Will first swap 8800gt and 9800gx2. So 8800 now goes on Slot-2 and 9800 on Slot-1.

If no luck with that, I will take some fresh air and think about bring my HDMI TV close to my macpro. :)
 
well the blue screen is what is displayed on secondary displays when the primary is sitting at the login window.
 
you are correct about that.

And when I swaped the cards, the system was stuck a bit earlier, on the gray apple. i could still access everything from SSH. but when I tried to to use anything CUDA/nvidia related, the system crashs. AKA, if I tryed to access the cards, crash.

I am swaping back. 8800gt goes back to Slot-1 and 9800gx2 goes to Slot-2.

I remember I edited the Info.plist from the files below to add 9800gx2 strings. Maybe thats why my system can recognize the card, after the 8800gt EFI is in action. It's like that the 8800gt EFI validates all nvidia cards connected, even the non-EFI ones.

Files I modified to add 9800gx2 string:
NVDAResman.kext
GeForce.kext
NVDANV50Hal.kext

I will remove the strings and see what happens.

If you guys want me to spot posting my progress (aka spamming the forums), please let me know.
 
By no means, keep posting as you make progress. I guess it's not *that* surprising because as OSX displays, they are just G92 chips.

Nice to see someone actually doing something instead of talking about it.
 
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Just to add:

If I boot with all 3 nvidia cards inserted (one 8800gt and two 9800gx2), I get a smoth boot and can login on my macosX.

MacOSX recognizes them as G92.

I can access the cards and make them process stuff via CUDA.

Code: 
$ ./deviceQuery 
There are 3 devices supporting CUDA

Device 0: "GeForce 8800 GT"
  Major revision number:                         1
  Minor revision number:                         1
  Total amount of global memory:                 536674304 bytes
  Number of multiprocessors:                     14
  Number of cores:                               112
  Total amount of constant memory:               65536 bytes
  Total amount of shared memory per block:       16384 bytes
  Total number of registers available per block: 8192
  Warp size:                                     32
  Maximum number of threads per block:           512
  Maximum sizes of each dimension of a block:    512 x 512 x 64
  Maximum sizes of each dimension of a grid:     65535 x 65535 x 1
  Maximum memory pitch:                          262144 bytes
  Texture alignment:                             256 bytes
  Clock rate:                                    1.51 GHz
  Concurrent copy and execution:                 Yes

Device 1: "G92-450"
  Major revision number:                         1
  Minor revision number:                         1
  Total amount of global memory:                 536674304 bytes
  Number of multiprocessors:                     16
  Number of cores:                               128
  Total amount of constant memory:               65536 bytes
  Total amount of shared memory per block:       16384 bytes
  Total number of registers available per block: 8192
  Warp size:                                     32
  Maximum number of threads per block:           512
  Maximum sizes of each dimension of a block:    512 x 512 x 64
  Maximum sizes of each dimension of a grid:     65535 x 65535 x 1
  Maximum memory pitch:                          262144 bytes
  Texture alignment:                             256 bytes
  Clock rate:                                    1.51 GHz
  Concurrent copy and execution:                 Yes

Device 2: "G92-450"
  Major revision number:                         1
  Minor revision number:                         1
  Total amount of global memory:                 536674304 bytes
  Number of multiprocessors:                     16
  Number of cores:                               128
  Total amount of constant memory:               65536 bytes
  Total amount of shared memory per block:       16384 bytes
  Total number of registers available per block: 8192
  Warp size:                                     32
  Maximum number of threads per block:           512
  Maximum sizes of each dimension of a block:    512 x 512 x 64
  Maximum sizes of each dimension of a grid:     65535 x 65535 x 1
  Maximum memory pitch:                          262144 bytes
  Texture alignment:                             256 bytes
  Clock rate:                                    1.51 GHz
  Concurrent copy and execution:                 Yes

As you can see. Not only MacOSX recognizes, but CUDE enable them to be used via the API.

However, I cant get them to display anything. The only port I didnt try to connect something, was the HDMI port. I am trying to exaust all alternatives before go grab my TV to plug in the HDMi port.
 
Woot!

After almost 24 hours without sleep, I finally got my 9800gx2 fully functional (as my default display and everything).

System:
Apple MacPRO (2x 2.8Ghz quad-core) (NOT a hackintosh)
6GB RAM
NVidia 8800GT (Apple upgrade kit)
NVidia 9800GX2 (Retail one. Bought eVGA from newegg)

Tomorrow I will post more details and pics of the 9800GX2 working under MacOSX 10.5.5 on my MacPro.

One last note. I F***ing hate Apple for this. If it took me only 24 hours wihtout sleep to make this work. Why the hell they don't make it available for everybody. I paid a LOT of money for this computer. Plus another big one for the two 9800GX2. PLUS some more for the 8800GT upgrade kit, just so I could use 8800GT EFI-enable firmware to "validate" the 9800's for MacOSX.

Next time I will only get all this money and create a customized hackintosh and save all the headache......
 
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