I've got a Cooler Master V8 I picked up quite a while ago to use with the processor I was using at the time - Phenom II 720. It worked fine, was quiet, etc. etc. About four months ago, I picked up a C3 Phenom II 955, and went about disassembling my system for the processor upgrade. I noticed that the heatsink contact with my Phenom II 720 was not exactly even - it was pretty much limited to the outside edges of the heat spreader (based on the patterns from the thermal grease). The 720 never ran hot, even so. It was an early 720, and the overclocking never got high enough to make that an issue, apparently. No matter what heatsink I was using, I couldn't get more than 3600 stable with the processor.
I put in the 955, used a little AS 5, and started using my system. The 955 at stock voltage(1.4v on my 790FX board) runs quite a bit hotter than my 720 did, and the V8 didn't seem like it was able to cope. I got ticked off enough to disassemble again, and when I removed the heatsink I noticed that it has the same contact pattern as it did with the 720. The machined contact surface of the V8 seems flat enough (with a metal straightedge), and the bracket doesn't look like it's bent in any appreciable way, but there's definitely something screwy here. Maybe I'm not torquing it down properly? I did use a cross-pattern, just like it was a four-lug wheel on a car. At 1.4v I was able to get 3900MHz or so before the CPU would overheat and shut down. Even at 3200 and 1.4v, the V8 would run upwards of 58' C after a short period (15 minutes or so) of HandBrake encoding.
Right now I'm back to using my old Zalman 9500 (a holdover from when I had a 5000+ BE Athlon x2), which is really no match for the CPU. I have the CPU undervolted to 1.29v at stock clock, which is stable, but it still gets pretty warm on the Zalman (reported temp of 51' C when using HandBrake and 80% load). If I set the voltage back to 1.4v, it heats up too quick to really even run at 3200, so I'm kind of stuck (3200 is about as high as I can get on 1.29v before I start having stability issues).
Has anyone else used one of these Cooler Master V8 heatsinks with AM2/AM3 CPUs? Maybe it's just junk for the socket, which I'm willing to accept. If it is, I'd appreciate any suggestions on an AM2/3 cooler I can use with the 955 to help bring the temps down. I don't necessarily need to run at 3900, but I'd like to run it higher than 3200.
I've got an older Antec 900 case, with the solid (no window) sides installed on both sides.