OCC has published a new review on the VisionTek Radeon HD 3870 X2 Overclocked Edition

Overclocking a pre-overclocked card? Can it be pushed any further? The answer is yes. It didn't take me long to discover that this video card does not like to be pushed, but I was able to obtain a minimal overclock on the already overclocked beast of a video card. I reached 850MHz on the core clock from the stock frequency of 840MHz, and on the memory I obtained a frequency of 975MHz over the stock 960MHz. It's not much, but we'll see if it gives a performance increase at all.

VisionTek Radeon HD 3870 X2 Overclocked Edition Review