Cons: Brackets. No instructions ! I may not have installed the heatsink correctly. When I turned on my PC the fan started spinning just fine but it was really loud. My CPU temp climbed all the way up to 98 degrees Celsius. I had to reinstall my stock heatsink which keeps the temp down around 48 degrees.
Summary: Maybe I didn't install it correctly but the fan was spinning. I was shocked that my CPU temp increased by 100%. No instructions were included. Needless to say this is going straight back to Newegg. I'll get a higher end heatsink from another manufacturer.
Cons: After installing it my i5-750 CPU (2.72 GHz) temperature skyrocketed to 98 degrees Celcius. My stock heatsink kept it at 48 degrees. The fan is way too loud. The brackets were difficult to install on an Asus mobo (P7P55-M). No instructions included.
Summary: I had to use a pair of pliers to "straighten" my CPU clasp on the motherboard to make this cooler fit. The design is a bit unorthodox; instead of the usual plastic pins that clips into the motherboard, it uses the CPU clasp instead. Some modification may needed in order for this to fit.
Summary: It is also very large. Make sure you have enough room in your case for it.
Pros: Very hefty and sturdy heatsink. Looks like it could take some punishment.
Cons: VERY hard to install. When trying to install this on my Biostar mobo, i had to remove the processor casing to fit the base on. This made it very difficult for the processor and heatsink to be seated correctly.
Summary: These are solid coolers for any platform even though they're designed for servers. Great for my gaming computer.
Pros: It's not gaudy and it will keep your CPU cool. Got it sitting on a Core i5 2.66ghz overclocked to 3ghz. A modest, but stable configuration.
Cons: There's no real way to see what direction the air flows in until you actually power the fan up. Note: You're going to want to point the fan at the front of your case. It blows air back across the heatsink and out of the rear of the case.
Summary: I purchased both K555 and K650 because I wasn't sure about any of them fitting in the case and amount of cooling that they provided. This one gets the job done. Xeon 3450 under 8 threads of prime95 heats up to 59 celsius (compared to 73 with stock cooler) It does such a great job because of horizontal airflow design (as opposed to coolers with vertically mounted fans).
Pros: Fits 2U server chassis nicely. Cools 14 degrees lower than stock Intel cooler Easy to install