Just because there are two cores does not mean that overclocking the GTX 295 is any harder than overclocking a single GPU core video card. The stock clocks of 576MHz on the GPU cores and 1000Mhz on the memory were easily exceeded by a large margin. I just kept bumping the core and memory clocks up until I showed some visual artifacts and then backed it down until these were gone. I was able to reach 683 MHz on the core and 1197MHz on the memory. These represent overclocks of 20% on the GPU cores and 25% on the memory at 107MHz on the GPU cores and 198MHz on the memory. Both pretty sick on air.