[H]ard|OCP has had a chance to take the time to really see how well the R9 290X can overclock, as frequencies get lower as heat increases a quick gaming session is not enough to truly represent the performance of this new GPU.  The ASUS R9 290X DirectCU II OC offers a custom cooler which demonstrated the overclocking potential of this GPU on air cooling, or at least this specific GPU as we have seen solid evidence of performance variability with 28nm Hawaii GPUs.  You should read the full review to truly understand what they saw when overclocking but the good news is that once they found a sweet spot for fan speed and voltage the GPU remained at the frequency they chose.  Unfortunately at 1115MHz the overclock they managed was only 75MHz higher than the cards default speed and while that could beat a stock GTX 780 Ti, the NVIDIA product overclocked higher and proved the superior card. 

"We will take the ASUS R9 290X DC2 OC custom AMD R9 290X based video card and for the first time see how well the 290X can overclock. We will also for the first time compare it to an overclocked GeForce GTX 780 Ti video card head-to-head and see who wins when overclocking is accounted for."

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