PowerTune gets the blame for differences in performance of press and retail cards.

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Shortly after the R9 290X launched in November, reports came in that retail cards were noticeably slower than the cards given to the press to review. PC Per and Tom’s Hardware, amongst others, noted that the retail cards had a clock speed approximately 6.5 percent lower than sample cards.

As PC Per and Tom’s Hardware note, there were observable changes in the retail card’s clock speed during gameplay as the card went from “cold” to “hot”. Clock speeds began near the quoted 1000 MHz, but trickled down from there. During testing, PC Per and Tom’s Hardware’s retail cards both started at 1000 MHz but were stuck much below that after a few minutes of gameplay: PC Per’s off the shelf card went down to 827MHz while Tom’s Hardware’s hit 727MHz.

For it’s part, AMD PR sent out this statement on Friday (North America time) that was widely published:

Based on feedback from the enthusiast community, we’ve implemented an all new PowerTune mechanism in the AMD Radeon R9 290 series that exploits the full capability of the individual GPUs rather than clamping performance to a least-common-denominator type of capability level. This has the advantage of improving overall performance but does result in some degree of performance variability. These changes will also result in some degree of run-to-run test variability based on environmental and operational conditions in un-controlled test environments.

The range of performance differential is not expected to meaningfully change the user experience but we’ve taken note of recent reports that the degree of variability is higher than expected. Reasonably we would expect the variability to occur both above and below the performance of the press samples, however it appears that most reported performances are biased towards the low side.

It is important to note that is it to be expected that the more thermally limited the setting the more variation can naturally occur. AMD Radeon R9 290X, by default, ships with two default BIOS settings for different acoustic levels and the “Uber” setting was designed to limit the level of thermal throttling and comparisons in this test mode are more consistent. Furthermore, AMD have implemented comprehensive PowerTune controls within the OverDrive panel of Catalyst Control Center and users can tweak to their own desired balance between acoustics and performance.

AMD said that it is “actively investigating” and will update the public with its findings when it concludes its investigations.

Via: Tech Report