Retail Radeon R9 290X cards may be slower than press samples
 

Modern CPUs and GPUs employ turbo mechanisms that adjust frequencies based on various factors. Although they aspire to higher speeds, these clock-boosting schemes have well-defined base frequencies that guarantee a minimum level of performance. Or most of them do, anyway. AMD defied convention with its Hawaii-based Radeon R9 290 and 290X by only publishing the peak burst frequency for those cards. We know the GPU speeds under ideal conditions, but there's no minimum baseline.

Our reviews of the Radeon R9 290 and 290X illustrate that both cards have trouble maintaining their peak boost frequencies while running games. As the GPUs heat up, the clocks scale back from their peaks, and frame rates ...

http://techreport.com/news/25609/upd...-press-samples