AMD Radeon HD 4870 X2 CrossFireX performance review

Rather inevitably we closed out our review of ASUS' EAH4870X2 TOP, based on AMD's Radeon HD 4870 X2, with the entirely predictable discussion of how it is the fastest graphics board ever and so on - Exactly what you'd expect from two RV770 cores with a 1GB frame buffer apiece, in other words.  So, how do you make the faster thing ever even faster?  You put two of them together in a CrossFireX configuration, that's how.

It just so happened that we ended up with the ability to enjoy such a configuration, and when we found time away from giggling with glee at the thought of gaming with over 4 Teraflops of computing power and a 4GB total frame buffer, we sat down and actually put our serious hats on to test just such a configuration for you, our beloved readers.  Two Radeon HD 4870 X2 boards working in tandem is, of course, overkill for the vast majority of you reading this, but beyond that, just how well does performance accelerate beyond two GPUs, and are there any real benefits from putting together such a configuration?  There are certainly still some interesting questions to be answered, so join us as we check it out in search of the answers.