I’ve been asked a couple of times now whether the Radeon HD 2900 XT 1GB runs higher frequencies than the 512MB version and it seems that many are convinced that the GPU runs at 825MHz and the memories at 2200MHz. This is not true. The only card that runs at these frequencies is the one sold by Canadian PC builder Extreme PC. Extreme PC was the first to announce the availability of the Radeon HD 2900 XT 1GB, along with Diamond Multimedia. Extreme PC’s card was overclocked though and this caused the misconception that all Radeon HD 2900 XT 1GB cards were using higher frequencies than the 512MB card. They don’t, they have the same GPU frequency as the 512MB version which is 743MHz and 2000MHz for the memory chips, the same as always.
The fact is that the Radeon 2900 XT 1GB is actually slower than the 512MB version when you start overclocking the cards, this is due to the much higher latencies of GDDR4. This was first registered back with the Radeon X1950XTX and its GDDR4 chips, and is still a factor as bandwidth is not the biggest problem when overclocking Radeon HD 2900.
