Are the stock heatsinks that come with these any good for overclocking single cores? I've heard they have a couple of heatpipes. I'm planning to buy a retail 165, use its stock cooler on my current 146 and use my existing XP90 on the 165. One of these will go in my main machine and the other one in a second computer I'm setting up. (haven't decided which will go where, depends on how well the 165 overclocks)