CrossFireX Arrives: First Look at 3 and 4 GPUs in 2 Card Setups
by Derek Wilson on March 7, 2008 12:05 PM EST- Posted in
- GPUs
We previewed AMD's CrossFireX technology a couple weeks ago, but today a WHQL drier is available that supports more than two AMD GPUs. In order to do this, AMD employs Vista's Linked Display Adapter (LDA) technology to make the collective GPUs appear to the system as a single virtual device. While this allows for more flexibility in GPU configurations, there are some drawbacks that we will talk about shortly.
The new Catalyst 8.3 is a milestone release for AMD that brings, in addition to Vista LDA support for more than two GPUs, a number of new features. These are (from AMD's documentation):
ATI Hybrid Graphics Support: The ability to use integrated and discrete graphics in hybrid mode to support either power saving (disabling the discrete graphics card) or to enable the integrated and discrete graphics hardware to share the graphics load. This is only available with lower end graphics cards and integrated chipsets using the 3200/3300 series hardware.
Anti-Aliasing enhancements: AA support for all UE3 titles (Unreal Tournament 3, Gears of War, Rainbow Six, etc.) through the control panel. Support for edge detect filters plus Super AA was slated to be in this release but it was pushed back. Tent filters can be enabled with Super AA, but edge detect will be coming soon.
Digital Panel GPU image scaling: The option to enable image scaling for maintaining aspect ratio of a display has been added. Additionally, the GPU itself is now used to scale the image if the check box is ticked. NVIDIA has had this for a while and it's good to see AMD adding support for this.
Advanced Video Quality controls: An edge enhancement slider has been added to adjust the sharpness of the video playback, along with a noise reduction slider. Having variable adjustment for these kinds of features is a very welcome addition and something we've been wanting ever since noise reduction became a hot topic in video decoding.
HydraVision for Vista: Multiple monitor and virtual desktop manager with support for hotkeys and tools to help keep things organized.
Let's take another look at CrossFireX now that we are allowed to test it on Intel hardware and compare it with competing solutions.
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kilkennycat - Saturday, March 8, 2008 - link
Multi-chip hybrid substrates with widely-spaced dies can help to spread out the heat rather nicely and help keep the overall yield up too, as Intel has demonstrated with the quad Core 2 processors. I fully expect hybrid substrates to become a popular interim solution to the need for masively-parallel processing GPUs -like IBMs 20-chip solution for their big number-crunchers. The hybrid/chip combo- architecture can be designed to externally emulate a single GPU. Also a very nice way of adding some extra local memory if necessary.DerekWilson - Saturday, March 8, 2008 - link
i agree that this is good direction to go, but even with intel we've still got dual socket boards for multicore chips ...the real answer for the end user is always get as fast a single card as possible and if you need more than one make it as few and as powerful cards as you can.
e6600 - Saturday, March 8, 2008 - link
no crysis benchies?Slash3 - Saturday, March 8, 2008 - link
Crysis is broken as a benchmark... despite all pre-release hype, the game seems to scale very badly across multiple cores and multiple GPUs. It's is kind of unfortunate, as if there's one game that could benefit from efficient scaling, it's Crysis.JarredWalton - Saturday, March 8, 2008 - link
I'm curious to see if version 1.2 fixes anything... it might. That just came out yesterday, so I don't think many have had a chance to look at whether or not performance changed.[Just checked]
At least for single GPUs, I see no real change in performance. I haven't had a chance to test multi-GPU, and all I have right now is SLI and CrossFire. Could be that v1.2 will help more with 3-way and 4-way configs. We'll see.
DerekWilson - Saturday, March 8, 2008 - link
there was no perf benefit at all from going to 3 or 4 gpus ... we saw this in our preview and when we tested the 8.3 driver. we mention that on the test page ...