Check for your CPU's waste heat production with Radiate (in downloads section). Then see whether it is more than 60% of the 72W TEC you have. From most manufacturer spec charts I've seen, TECs seem to have a max. heat removal of about 60% of the input power (when running at Vmax voltage). So, you'll remove a max. of 43.2W with that TEC but to be safe I'd keep a safety margin of about 20% (9W) away from the max so your CPU, at O/C speeds, should not produce more than 34.2W of heat. At these heat loads, you can actually get away without water cooling -just modify an Athlon HSF to fit.