I would recommend the Thermalright AX-7. Depending on your tolerance for noise, you can get a speed adjustable Enermax or the Vantec Tornado.
I had the FOP-32 from back in the day sitting on my Athlon 1.2Ghz. Running at 1.85v and 1.33Ghz I had temps of around 52C full load. I put on the AX-7, and the much quieter Enermax fan, and after bumping the voltage up to 1.95v and the speed to 1.47Ghz, I was running 41C full load.