The most overclockable P4 is the 1.6A. The most overclockable P4C is the 2.4C, but only if you get a motherboard that can handle in the neighborhood of 300 FSB. I would go with the 2.6C. Even though you could theoretically get it the same speed as the 2.4C, you would get higher realistically with the 2.6, and you might be able to run the memory faster ( a 5:4 vs. a 3:2) with the 2,6, which would give you better performance.