Yea Frostytech is great! According to benchmarks I've found that these CPU coolers to be the best at cooling and that should fit in a 4U server case (if you can find them and if they are worth the extra couple degrees):
-Tuniq Tower 120 Extreme Rev 1
-Scythe Katana 4
-Thermaltake Contac 21 (Similar to the CM TX-3 and also allows adding a 2nd fan)
-Coolermaster TX-3 (similar to the 212+ and Evo but smaller and cheaper, uses a 92mm PWM fan, and allows for a 2nd fan, but does not work for Socket 1366)
-Raijentek Aidos (similar to the CM TX-3 and Contac 21 but cannot add a 2nd fan)
-Xigmatek Loki SD963
-Silenx EFZ-92HA3
-Iceage 120 Prima Boss or Iceage 120 Plus
I've done a lot of looking, but just ended up getting the Supermicro SNK-P0040AP4 heatsinks as I was able to get a bunch of them for pretty cheap off ebay and I knew that they would be compatible with my server motherboards. If I'd do it again, I'd probably get the Coolermaster TX-3 or the Thermaltake Contac 21 so I could add 2 fans to it and hope that I could mod the mounting bracket like you
@chinesestunna did.
Oh and
@Marsh how do those Intel E97381 heatsinks work as far as cooling? Do they keep things pretty cool? I know these are servers so they can run pretty hot, but I like to keep things as cool as possible including the motherboard and components. It's probably from building mainly office/gaming pc's. Thanks!