I just trow the voltage on 1.55 / 1.6 volts and HTT to 300MHz, HTT devider to 3x or 600MHz (600 with 200 / 900 with 300, normal @ 800 with 200). Just using stock cooling. That would make a Sempron64 2500+ run @ 2100MHz, 2600/2800+ @ 2400MHz, 3000/3100+ @ 2700MHz if the CPU holds it . 2700 would be most likely the max or you need more voltage and indeed a better cooler. EDIT: The 3700+ works on 2.4GHz, You could crank it up like 3GHz with d*mn good cooling but that will be the same for a 3000+. If you tweak it, then buy one of the cheapest models .