Dual nVIDIA GeForce 8800 GT GPUs

This does indeed help!

Your set-up shows that two 8800 GTs can run together on a Mac Pro, which is part of what I was hoping was the case.

I suspect (and I'm guessing here) that your performance would improve considerably if you connected your two 8800 GTs with a SLI ribbon cable.

FYI, here's what they look like: www.sidewindercomputers.com/flslicafornv.html).

It seems that a key function of the SLI ribbon cable is to take the 8800 GT exchange bandwidth load off of the motherboard.

Another function of the SLI ribbon cable is to be enable and use nVIDIA's SLI technology without it being embodied in the motherboard (but two 8800 GTs are a requirement here - one 8800 GT will not enable the SLI feature).

If I learn more, I'll keep you posted.

Good luck and many thanks!

tyvol

Wow, I'll look into the 9800 GX2!

I hope it will run on 1st generation Mac Pro's.

If it does and the price is not over the moon, two processors in one slot seems like the logical way to go.

Many thanks for the heads-up!

Cheers,

tyvol

Great feedback!

I'll take your word for it, but I'm now running two 8800 GT's with an SLI ribbon connector (w/32 bit Vista), and I can't tell if the SLI feature works, simply because I don't know how to test it.

One thing you might want to know is that the first 8800 GT must be in slot 1 to get the 16x factor. The second 8800 GT needs to be in slot 4 to get the 8x factor. Slots 2 and 3 don't allow maximum performance (at 1x or 4x).

A humble observation is that, using my ATI X1900 XT, Crysis would not automatically run at this game's maximum graphics settings. It was still pretty good, though.

With the dual 8800 GTs however, Crysis automatically puts the graphic settings at their maximum, and the results are terrific.

Another observation is that using the 8800 GT's, Vista's "Performance Experience" test increases the "3D gaming" to 5.9 over 5.8 with the X1900 XT.

Not much, but it's something.

I don't expect SLI to work on my 1st generation Mac Pro, but I'd sure like to be able to test if it works using Vista (32 bit).

I know, I know, but then again I have hopes in winning the lottery as well...

More guidance is appreciated!

Cheers!

tyvol

Well,
I'm more comfortable with ordering direct from Apple.
Please note though, Apple clearly indicates that there are two versions of the 8800 GT.
Not an issue for you, but 8800 GT for the second generation (2008) Mac Pro will not work on the first generation (2007) Mac Pro.
My two 8800 GTs work fine in my first generation (2007) Mac Pro.
They must to use slots 1 (16x) and 4 (8x) for best available slot bandwidth.
They each have to also be connected to power from the motherboard, and this is no problem but note that there are only two auxiliary power connectors on the motherboard.
The 8800 GTs are also connected together by an SLI ribbon cable.
Alas, nVIDIA's SLI is not enabled for either Mac OS X or Vista.
The 2007/2008 Mac Pro's won't allow this (so far).
However, the two 8800 GTs are some faster that the X1900 XT.
Crysis settings are automatically upgraded from Medium (X1900 XT) to High and the Performance Experience rating for 3D gaming under Boot Camp Vista 32 bit went up a notch.
There is a new GPU you may now wish to compare against my more expensive solution, and that is the ATI HD 3870. Bare Feats shows it tests out faster in almost all respects than an individual 8800 GT ( http://www.barefeats.com/harper16.html). That's because it contains two processors in one PCI Express 2.0 slot (this 3870 is backward compatible to the 2007 vintage Mac Pro's (dubbed Cloverdale) and 2008 vintage (so far) Mac Pro's (dubbed Harpertown)). Unfortunately for me, Bare Feats doesn't have a head to head comparison of the 2 processor 3870 GPU to two 8800 GT GPUs additionally connected via SLI ribbon cable. Such a test would, I believe, make the 8800 GTs very, very competitive, but at a much higher price. But note that the price of the 3870 is around $200! I wish I'd known about it sooner...
Hope this helps!
Cheers,
tyvol

Hatter always gets to the point ever so quickly.

My personal experience is that my dual 8800 GT (with SLI connector) is a way better performer than the X1900 XT on my Mac Pro.

As for the ATI 3820 2x, I don't have access to one of these.

I would need one in order to be able to responsibly give my personal experience regarding its performance.

My hunch was that the dual 8800 GT with SLI connector is even a better performer as compared with all other GPU options out there for the Mac Pro.

Hatter pointed us all to extensive tests that bear this out, far more objectively than I could.

As usual, Well Done Hatter!

And, many thanks!

Cheers,

tyvol

rob_Art,
Good input!
Question: Is the ATI Crossfire effect you mention, published yet on BareFeats.com?
Can you tell us what ATI GPU this is (if you can't, that's Ok)?
I'm most grateful for your input on this topic!
Cheers,
tyvol