techPowerUp! has posted a review on the X800 GTO2 to X850 XT Mod

We recently got our hands on one of the new X800 GTO2 cards from Sapphire. These limited-edition cards use an R480 core from ATI, which is limited to run at 12 pipelines. We were surprised that these $200 cards can be easily modded to run at 16 pipelines. During testing, our sample could be overclocked to run at X850 XT PE speeds completely stable - $300 saved.

X800 GTO2 to X850 XT Mod