Confirming the results that Ryan and other sites have seen are the results of [H]ard|OCP's testing of two different retail R9 290X GPUs against a pair of press sample cards.  Much as with Ryan's findings even using the newer Catalyst 13.11 Beta 5 driver, Quiet mode performance varies far more than Uber mode does but even Uber mode displays some differences between models.  However they draw a slightly different conclusion based on their experiences, determining that the variance is not just a matter of press samples versus retail cards but a variance between any and all 290X GPUs.  The complexity of this huge chip is such that the differences in manufacturing process and tolerances are to blame and some cards will simply be better than others.  They also are disappointed by AMD's marketing team, citing that the key is 'With NVIDIA GTX 600 and 700 series the video cards are "running faster than advertised" and with AMD R9 290X the video card is running "slower than advertised."'

"The AMD Radeon R9 290X arrived recently with a high level of performance, and a high level of controversy. There have been reports of performance variance between Radeon R9 290X video cards. We have two purchased retail cards today with stock cooling that we will test and see if performance variances exist."

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