The Zalman CNPS5700D-Cu uses a neat little clipping and spring system to stay in place on a standard socket 478 heatsink retention mechanism. Rather than using an external set of metal spring clips which can effectively limit the overall size of the heatsink, Zalman has engineered the spring into the center of the CNPS5700D series.

The spring holds the copper fins which form the core of the heatsink in place, and allows that entire assembly to move up a few millimeters under increasing tension. As a bonus I suppose, if you've been less then careful about installing the heatsink retention mechanism onto the motherboard and it's a bit crooked that shouldn't matter. The fulcrum of the internal spring is dead center, so the copper heatsink assembly can tilt a little to the left or right to accommodate the processor fully.

The small clips just need to be pushed in when the heatsink is keyed into the heatsink retention mechanism and the internal spring will hold everything in place. The clips are not spring loaded, but do have a little catch so even with no processor installed you have to push down in order to remove the heatsink. The system is really simple to use, but if the heatsink can sit properly, it won't lock into place at all.

The CNPS5700D-Cu is a big heatsink and it isn't going to fit into every single case with the air duct on top. At the very least, the air duct can be unscrewed and the heatsink will then fit into basically every case - but that really isn't what we want is it? Now, there is nothing to be done about the height of the heatsink with the fan duct (it measures 150mm tall, 67mm without the air duct).

The issue we encountered while dry fitting the heatsink into a standard Antec white-box mid-tower had to do with the width of the air duct, or more correctly, the flange at its base. This part of the air duct stands 15mm proud of the rest of the unit, so in situations where the motherboard has the socket flush to the top of the PCB, and the case keeps the motherboard and powersupply very close together, the heatsink just might not fit.

From the edge of the heatsink retention mechanism to the side of the powersupply in our case measured just 14mm. It is really hard to give exact measurements for clearance since the placement of both the processor socket, and the layout of the case are important, but as a general rule, if the socket is flush to the top of the board, and the powersupply is flush to the top of the motherboard tray, the Zalman CNPS5700D-Cu is not going to fit. Not with the air duct installed anyway.

There is one way around this, but it may not work in all cases so just bear that in mind. Since the edge of the plastic is relatively thick (it measures 4.5mm from the screw slot) it could be made to fit by filing down the flange a little. If the air duct is significantly causing the heatsink to not sit properly this won't work, but for small discrepancies like our situation above it is a quick and easy way to ensure the heatsink mounts on the processor, and in the socket, properly. A quick suggestion though, make sure you aim the air duct first, and then file down the offending edge.

Now, let's have a look at the heatsink with that blue-LED fan from Akasa we were telling you about; after all, it does look kinna neat....