SLI works

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Level 1

45 points

SLI works

Got my Mac Pro with 2x NVidia 7300 cards today. Used the PCI Express bandwidth config app in OS X to set slots 1 and 2 to 8x mode then I tested SLI in WinXP using the modified ForceWare 85.96 drivers (modified to work on any chipset). The drivers recognized the cards straight away and offered to enable SLI mode and it appears to work without any problems.

Did a quick test after installing XP and the drivers from bootcamp (no other tweaks yet)

3dmark2006 (free edition) results for one card:
3DMark Score 1642 3DMarks
SM 2.0 Score 595 Marks
SM 3.0 Score 551 Marks
cpu 3861

3dmark2006 (free edition) results with SLI enabled:
3DMark Score 3091 3DMarks
SM 2.0 Score 1162 Marks
SM 3.0 Score 1046 Marks
cpu 3861

Will do more tests when I get a chance.

Mac Mini G4, Mac OS X (10.4.7), Mac Pro

Posted on Aug 23, 2006 4:46 PM

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Answer 1

boli

Level 1

75 points

Aug 24, 2006 5:20 AM in response to CW2k

Interesting. 🙂

I was wondering if the cards still work in Mac OS X, as I assumed it would require connecting the cards with an SLI connector, but then I noted that .

So, both cards should still work just fine in OS X, right?

Quad G5 Mac OS X (10.4.7) 4 GB ECC RAM, Raptor 150 GB, Seagate 750 GB, GeForce 7800 GT

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Answer 2

CW2k Author

Level 1

45 points

Aug 24, 2006 6:52 AM in response to boli

My test was done with an SLI bridge connector, the cards still seem to work in OS X without any issues.

If you don't use a bridge I believe you can get a performance hit.

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Answer 3

boli

Level 1

75 points

Aug 24, 2006 7:02 AM in response to CW2k

1. Excellent. 🙂

2. Really? I have no experience with SLI, I just noted the NVidia page linked above says:

The NVIDIA GPUs marked with an asterisk in the list on the right do no use the SLI connector.

BTW, Marked are all GF 7300 series cards (LE/GS/GT).

It might be worth testing without SLI connector, for the benefit of those who don't have an SLI connector lying about... 😉

Quad G5 Mac OS X (10.4.7) 4 GB ECC RAM, Raptor 150 GB, Seagate 750 GB, GeForce 7800 GT

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Answer 4

Aug 24, 2006 8:12 AM in response to boli

Woah that is really cool. So OS X has SLI support too? All my OS X naysaying "friends" said that the Mac Pro will not support SLI but if it does then I'm not gonna let them live this one down ; )

This would be great since I could just stick with NVidia and add an extra card when I need more oomph.

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Answer 5

T0pcat

Level 1

0 points

Aug 24, 2006 8:50 AM in response to CW2k

Well i tested the 7950GX2 tonight and it boot windows fine and the frame rates were Perfect, 1920 X 1600 smooth as BUT 😟 On booting into OSX (with the 7300 still in there as well) i got the dreaded Grey screen kernel panic i dont get this with a 7800 that i have tried.......

Any ideas on where to start looking on how to resolve the OSX kernel panics ??

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Answer 6

Aug 24, 2006 10:32 AM in response to T0pcat

The video card needs to support EFI, and there needs to be drivers for it. My initial guess is you're getting a kernel panic because the video card doesn't have an OS-X and EFI friendly ROM image on it.

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Answer 7

Leonard

Level 4

1,705 points

Aug 24, 2006 1:35 PM in response to T0pcat

You definitely need Geforce 7950GX2 drivers in MacOS X. Without them you will get a kernel panic.

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Answer 8

JoshD

Level 1

89 points

Aug 24, 2006 2:21 PM in response to CW2k

can somebody else confirm this (that SLI works in OS X with the 7300)?

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Answer 9

boli

Level 1

75 points

Aug 24, 2006 2:32 PM in response to reckless ronin

I should have been more careful formulating my question, I meant to ask " do the cards still run as individual cards in OS X?", which I assume is what CW2k affirmed. So no SLI in OS X without driver/OS support.

At $150 for an additional GF 7300 GT it might be a viable option for some. Though for yet another $200 more the ATI x1900 XT is expected to be much faster (in both OS X and Windows), as well as occupy only a single slot.

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Answer 10

boli

Level 1

75 points

Aug 24, 2006 2:29 PM in response to JoshD

I don't think CW2k confirmed this, I'm afraid my question might have been a bit ambiguous.
Until further notice I assume that both cards do work in OS X just as two individual cards - not in SLI mode (which would require driver/OS support).

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Answer 11

CW2k Author

Level 1

45 points

Aug 24, 2006 3:27 PM in response to boli

In Windows the cards work as either 2 individual cards or in SLI mode.

In OS X the cards only work as 2 individual cards due to lack of SLI support in the drivers.

When switching between Windows and OS X you don't need to worry about changing any settings as everything is handled automatically (SLI is only enabled while the NVidia windows drivers are running)

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Answer 12

JoshD

Level 1

89 points

Aug 24, 2006 4:35 PM in response to CW2k

Wow. So does that mean that Apple or NVidia could release updated drivers for the 7300 to enable SLI or is this an EFI/BIOS issue?

Seems like if Apple does not do this they are encouraging users to stray from OS X in order to get more performance from their games.

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Answer 13

Aug 27, 2006 1:41 AM in response to CW2k

Im wondering if anybody did benchmarks with ATI X1900 on WinXP ... Would be very interesting to compare results.

G4 pb Mac OS X (10.4.7) 2GB RAM

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Answer 14

Aug 27, 2006 3:32 AM in response to CW2k

Great news! So it seems that there is a need for driver updates from Apple.

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Answer 15

Aug 27, 2006 9:13 AM in response to Eric Munson

Don't hold your breath. The paucity of video cards for the MacPro is a clear indication that Apple is not at all serious or concerned about providing gamers or media users with a variety of video cards. I am hopeful that they will support HD through the X1950 at some point, but I wouldn't hold my breath. As for SLI, I'll bet you dinner at a diner that we will see no official solution from Apple.

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