Im doing heavy compositing work with lots of layers and have noticed that my upgrade from Geforce 8800GT to GTX 285 saw an improvement in my work.

I am wondering if using 2 GeForce GTX 285 in SLI will yield better performance in After effects over a single Geforce GTX 285.
Can anyone confirm or deny?

In upgrading from a 4830 1gb to a 5850 1gb I didn't really notice a difference. From my experience high clock speed and the amount ram really make the most difference. This may change with the 64bit truly GPU accelerated CS5, but for CS4 it's not the case.

I previously had an 8 core 1.8ghz Opteron with 16gb of RAM, believe it or not my 2 core 3.8ghz Phenom II with 8gb of RAM is much faster for rendering. I actually benchmarked it with the different video cards, with and without the OpenGL Renderer enabled, I can see if I can find those if you want.

I am currently waiting for the new 6 core Phenom IIs where it will automatically ramp up cores for what you need, that in combination with the latest cards from nVidia or ATI I think will be a really good combo for CS 5.

Tyson,

Take a look at this KB article from Adobe regarding supported cards.

Graphics Acceleration (GPU) support in Adobe Creative Suite 4 applications (http://kb2.adobe.com/cps/405/kb405445.html)

I couldn't find reference to SLI mode using two cards, but maybe it will lead you to the appropriate answer. As far as I can tell, the application addresses the two cards as a single entity and accepts the resulted calculations. So if the calculations come back to the application (After Effects) that much faster, how could it not benefit?

There is no SLI support in CS4 and AFAIK neither with CS5/MPE.

In fact, none of the current high-prosumer NLEs such as Premiere support more than one GPU. This means that if you have two cards in SLI mode, only one of the cards is used. Similarly, if you have a dual-GPU card, only one of the GPUs on the card is utilized.

And yes, there is a significant performance difference between an 8800GT and a GTX285. Although the 8800GT theoretically supports CUDA acceleration, that GPU was introduced before the advent of CUDA. Hence, the 8800GT is no better than most of the lower-end NVIDIA cards in CUDA performance.

To the person who didn't notice much if any improvement going from an HD 4830 to an HD 5850, remember that Adobe seems to have been more pro-NVIDIA and pro-Intel lately. CS5 will no longer include hardware OpenGL acceleration support, and thus CS5 will default to the software-emulated OpenGL playback engine with a non-CUDA and non-supported card. This will eat up your CPU utilization and slow down performance significantly. And even the fastest AMD processors do not perform any better than a bottom-of-the-line Intel Core 2 Quad (Q6600) in Adobe's CS4 software.

Well that's an eye-opener

CS5 will no longer include hardware OpenGL acceleration supportI think that is in reference to PPro CS5 and its Mercury playback engine. AFAIK at this early point, AE will continue to use OpenGL and hasn't been mentioned as making use of Mercury.

We're in a cat-n-mouse game about the capabilities of software that hasn't yet been released so proceed with caution, especially when opening your wallet!