Zalman CNPS9900A: Avoid03 January 2011
In the past I have had good experience with Zalman coolers, being a lot quieter that the stock heatsinks normally included with CPUs. One of the problems with the classical Zalman "Flower" design is cooler clearance, as some of the more compact motherboards have components sticking up in awkward places. I did not feel like having to cross-check compatibility, so this time I decided to go for the CNPS9900A, which is tall rather than wide.
Unlike way back in the 1990s, the systems I built in the last decade have all been Athlon based, where the CPU cooler is clipped on. However for my most recent system I decided to get an Intel-based system, and on these the CPU cooler retaining brackets are bolted down. In this case I was attaching the cooler to an LGA1156 motherboard. Big mistake:
Those spring-loaded bolts are located underneath the cooler itself, and the screwdriver is at the shallowest angle I could manage. Anyone who knows what it is like to do up bolts/screws at an angle will understand why this is a bad thing to do. And to top it off, the edges of those thin heat dissipation fins are fairly sharp, and they did a good job of catching the top of my knuckles. Blood everywhere.
And the fun does not stop there. The retaining bracket bolts onto an underlying support bracket, which itself is bolted to the motherboard. Below you can see the underside (side that touches the motherboard) showing the nut a retaining bracket bolt attaches to:
I can assure you that this nut dislodges very easily, which is very annoying when you have already bolted the motherboard into the case. In the end I stuck a bit of blu-tak on the underside to stop the nut falling out, but it seems that all my attempted tightening at a silly angle had ripped the threads on the bolt and/or nut. 3 hours of sweat and blood later and the CPU cooler was still not attached. Eventually I was sufficiently pissed off that I gave up and ordered in a different heatsink.
Moral of the story: If you have an Intel motherboard, avoid the Zalman CNPS9900A like the plague. It looks like it was designed for Athlon systems where a central clip hold the cooler in place, and an Intel bracket was added as an afterthought. Even though the Socket 1366 brackets are slightly larger, they seem to be of the same design and hence flawed in the same way.