I was glad to see that the additional cooling was worth another 50+MHz over the reference cooling solution for a maximum speed of 1002MHz on the pair of Cayman XT cores. To run this number, it took a voltage bump up to 1250mv. Usually that brings on another challenge with increased heat, but the EK full-cover block assuages those fears. In all, I was able to squeeze a 122MHz bump (+14%) over the 880MHz clock speeds on the cores and a 238MHz bump (just over 18%) on the GDDR5 memory. The increased clock speeds definitely help with increasing FPS in games. The biggest upside for me, besides the higher clock speeds, is that the horrendous fan noise is gone at the upper edges of the clock speed range. This lack of fan noise was great, but it allowed me to hear the chokes in the power circuit screaming like stuck pigs when I put the screws to it. The PowerColor HD 6990 LCS is built with a reference card as the base, so this really is not a huge surprise. All in all, the reason for a liquid-cooled card pays off here with tangible increases in clock speed and therefore performance.



Link: Overclocekrsclub