You know what -- after testing the cards in a 3-way GPU configuration I must admit, I'm not disappointed... but I'm not happy either.
Overall performance scaling with three cards works well if it actually works, however it's at the high resolutions where you need to find the real difference, preferably 1920x120 and upwards.
Obviously rendering your games with three GPUs equals a lot of brute horsepower, so big that the rest of the PC might become a bottleneck for your graphics solution. That is however a luxury problem though but as an example, Fallout 3 at 8x AA at 1920x1200 performed as well as a 2-way 5770 setup as the processor (Core i7 @ 3.75 GHz) was literally holding back the GPUs from reaching the stratosphere.
It is going to be interesting to see how future high-end graphics cards will tackle this issue. Hopefully, graphics wise, some very demanding games will be released in the near future.
Next to this observation we admittedly did have some issues with a couple of titles... 3DMark Vantage weirdly enough did not show a higher GPU score, it was clearly rendering with two GPUs. Then Crysis Warhead acted really weird, by showing performance below a setup with two 5770 GPUs as well as Brothers in Arms: HH. Another title, Mass Effect would not run whatsoever.
The other titles we used like Far Cry 2, Fallout 3, COD5, HAWX, Anno 1404 (despite texture bug) all worked and scaled as we'd expect next to being CPU bound.
Fact remains that we had issues with four out of ten titles. And that poses a concern in my book. If CrossfireX with three cards works, it works perfectly nicely, kicking your gaming rig into the very high-end. If it doesn't... you'll be stuck at 1 or 2 way CrossfireX performance, or maybe even worse.
The bottom line: the 3-way GPU experience is a little so-so and I'm not sure if I really want to recommend you taking that path.
Dual (2-way) GPU Crossfire however works really well, and that's something we definitely can recommend. However if you were opting to spend 450-500 USD on a 3-way Radeon HD 5770 setup, we'd very much like to recommend you to wait on the upcoming Hemlock X2 graphics card or perhaps just go for the Radeon HD 5850 in 2-way CrossfireX. It's roughly the same money and performance, but will offer a much better overall game experience without many issues.
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