Attempting to overclock the R9 290X revealed that the GPU is basically already giving its all. We managed to extract another 90MHz (9% gain) for a core speed of 1090MHz. However, the card's GDDR5 memory skipped from 5GHz to 6.4GHz without any problems.
In Tomb Raider, we saw an 11% performance increase from our overclock, which was enough to boost the R9 290X within striking range of the GTX Titan.
Our overclock provided just 4% more frames in Metro: Last Light at 2560x1600, though you will notice considerably more performance at 1920x1200.
When testing our overclock in BioShock Infinite we saw a 12% performance boost, allowing the R9 290X to overtake the GTX Titan.