GeForce 8800 GTX (OC) working on 2008 Mac Pro under Vista 64!

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GeForce 8800 GTX (OC) working on 2008 Mac Pro under Vista 64!

While we were waiting for our GeForce 8800 GT kit to arrive for our new Mac Pro 3.2GHz 8-core, we decided to install Vista 64 on a Boot Camp partition. At the time we had the Radeon HD 2600 XT installed. We shutdown. Installed a PC version of the GeForce 8800 GTX. Powered up. Voila! It worked! It worked even better once we installed the Vista 64 drivers that came with it.

We just ran Prey benchmark at 1920x1200 "High Quality." We get 155 fps.
Compare that to the same Mac Pro with a Radeon X1900 XT which gets 64 fps
and a Radeon HD 2600 XT which gets 36 fps.

The latest, greatest Mac., Mac OS X (10.5.1)

Posted on Feb 7, 2008 2:28 PM

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Answer 1

Feb 7, 2008 7:26 PM in response to rob_ART

But how about in MAC OSX? Can it run ?

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Answer 2

Feb 7, 2008 10:18 PM in response to rob_ART

Can you give me the FPS for Crysis? The same resolution, with the highest quality setting you can test.

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Answer 3

Civrock

Level 1

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Feb 7, 2008 10:45 PM in response to rob_ART

Thanks for the info, rob_ART, sounds very promising. Getting my Mac Pro with 8800 GT in about a week, according to the order status, can't wait to try some games on it. 🙂

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Answer 4

Feb 8, 2008 2:02 AM in response to Civrock

My 'Pro with 8800GT shipped this morning (England) so we should all be receiving them soon. I have a GTX 8800 which I shall use in Boot Camp; I hope the PSU can take it!

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Answer 5

The hatter

Level 9

61,031 points

Feb 8, 2008 2:08 AM in response to rob_ART

Impressive. Looking forward to your next write-up.

Cinebench is pretty synthetic but a good way to compare?

People have been using 8800s under Windows on Mac Pro in the past, just no video signal during early boot (so couldn't see what was happening).

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Answer 6

rob_ART Author

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Feb 8, 2008 11:02 AM in response to Neal Jackson

I don't think the PCIe bus can handle both a GT and GTX 8800 which consume 146 and 178 respectively. That totals over the 300 watts rating of the PCIe bus. And it will require 3 power leads. There are only PCIe power 6 bit outlets on the motherboard.

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Answer 7

rob_ART Author

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Feb 8, 2008 11:27 AM in response to The hatter

Cinebench's OpenGL test is pretty useless since it runs in a 1024x768 window. I've found that it's as much influence by CPU as GPU.

I don't use it any more.

For Pro Apps, I use Motion and iMaginator. I'm hoping to add Aperture if I can create a measurable and repeatable test that stress the GPU more than the CPU.

For Games I use Quake 4, Doom 3, Prey, Halo, WoW, and UT2004 Flyby.

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Answer 8

Feb 8, 2008 12:39 PM in response to rob_ART

Are those wattage's peak or idling? I was hoping I could physically remove the 8800GT when installing XP/Vista and install the 8800GTX and nVidia drivers. Then when I put the 8800GT in the second PCI Express 2.0 slot ignore the "Found new Hardware" dialogues (do not show again) and assume that the PSU would not attempt to power both cards during the respective OS boots.

Hmm... The cabling is quite another matter. I'll have to see if benchmarking and fly-by testing makes swapping over the GPU card leads a worthwhile effort when gaming.

Any thoughts on this rob-ART...? You've played with these latest machines.

This contemporary "Pro" computer comes with an incredibly feeble PSU for a high-end PC which Apple claim "is already packed with power" one can further exploit and "Expand at will".

Message was edited by: Neal Jackson

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Answer 9

The hatter

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Feb 8, 2008 3:39 PM in response to Neal Jackson

900W PSU. There are two PCIe auxiliary 75W power connectors you need to connect.

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Answer 10

rob_ART Author

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Feb 8, 2008 7:28 PM in response to Neal Jackson

Those numbers should be maximum. The PSU can handle both cards at 900W but the PCIe bus has a 300W limit imposed on it regardless of where the cards get their power.

I'm not sure what would happen if one of the cards is just sitting there powered up without being connected to a display. It's probably best to shutdown the Mac and disconnect the power feed(s) to the card you don't need for the next startup.

What I really want is a GeForce 8800 GTX option from Apple that works under both Mac OS X Leopard and Vista 64. Why? Because it has the same chip set and same core frequencies as the Quadro FX 5600 for a fraction of the price. I'm not holding my breath, though. Another cool scenario would be dual GeForce 8800 GTs in SLI mode. Not holding my breath on that either.

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Answer 11

The hatter

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Feb 9, 2008 7:28 AM in response to rob_ART

Holding my breath, for a retail 2006-era capable 8800!

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Answer 12

rob_ART Author

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Feb 9, 2008 7:47 AM in response to rob_ART

I went back to my notes and realized I goofed on the wattage of the 8800 GT. Its maximum is 110 watts. As for the 8800 GTX, the 178 watt rating is extrapolated from the fact that a stock GTX draws 165 watts and our sample is overclocked to match the core frequencies of the Quadro FX 5600 (which uses the same chip set and is rated at 178 watts -- and also uses two PCIe power leads).

But that's good news. That means if you install both a GeForce 8800 GT and GeForce 8800 GTX in your Mac Pro (one for OS X, one for Vista 64), then the total wattage is 288 watts -- which is under the 300 watt limit for the PCIe bus. Yay.

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Answer 13

Feb 9, 2008 8:41 AM in response to rob_ART

That is indeed good news...I thought when I'd first considered this option that my calculations were within spec based on the 8800GFX I already have. I was also presuming the MacPro comes with two power supply cables for two cards but this may not be the case given another message in this thread. Can you tell me if the 'Pro comes with the necessary cabling or do I have to acquire a new cable?

I think I'll still choose to unplug which ever GPU card I'm not using just to save on power. The GFX will only be needed when gaming within the Wintel environment.

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Answer 14

Feb 9, 2008 9:18 AM in response to Neal Jackson

The power cables come with the graphics cards (if they need them) not the Mac Pro.

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Answer 15

The hatter

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61,031 points

Feb 9, 2008 9:39 AM in response to Neal Jackson

When you order the 8800GT from Apple, the package includes the necessary aux power cord, as did the X1900.

I have an 8600 GTS (PC, no OS X support) and even though it only needs 75W usually, I bought the extra Apple-approved cable from 3rd party just to be on the same side, which eVGA recommended using.

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