According to exact data we got today, the core/shader/memory frequency of GTX285 is 648/1476/1242MHz (2484MHz data rate) respectively. We can see obvious improvements comparing with 602/1296/1107MHz of GTX280. It’s noteworthy that the improvement of shader frequency has exceeded that of core frequency. In another word, the shader clock/core clock scaling of GTX285 is bigger than GTX280, which means slight improvement in performance.

http://en.expreview.com/2008/12/16/r...ia-gtx285.html