The first time I heard about the Thermaltake K450 heatsink was when I started my search for a CPU cooler for my Athlon 64 FX 55 in my SLI system. The problem I had was that the heatsink that was sent to me for my FX 55 was not meant for that CPU. I found this out by seeing my FX 55 temperatures soar to 70C when running Folding@Home. I knew this was way too high and headed to AMD's sight to find approved heatsinks. At that time, the only approved heatsink was the K450.