Diamond Radeon HD 4870 X2 XOC
 

we evaluate the Diamond Radeon HD 4870 X2 XOC. As you already know, the Radeon HD 4870 X2 employs two RV770 GPUs, each of which is complemented by 1GB of GDDR5 memory (for a total of 2GB frame buffer memory). The reference GPU clock speed for the 4870 X2 is 750 MHz, and the reference memory speed is 900 MHz. Diamond, however, boosted the XOC's clocks to 800 MHz and 950 MHz, respectively, making this one of the fastest 4870 X2 cards on the market.

http://hothardware.com/Articles/Diam...HD-4870-X2-XOC