Now, add in the fact that we've just finished a review on some of Akasa's LED fans and you can see how the next step evolved pretty quickly. Before we even tried to test out the CNPS5700D-Cu for its thermal performance we started playing around with it, and the results look pretty cool under the right light.

The heatsink doesn't come with blue-LED fan, but with a few twists of the screwdriver we quickly had the Akasa fan in place and were treated with a nice little effect courtesy of the copper heatsink's construction. Because the fins are all crimped at the base of the copper-fan assembly, the blue light from the fan was reflected off increasing the coolness factor by several fold.

We took a few shots of of the Zalman CNPS5700D-Cu with the Akasa blue-LED fan just so you can get a feel for what we saw, but before we get into that lets see exactly what we have here, and what restrictions you should be aware of before you try to install the Zalman CNPS5700D-Cu in your case. This review is going to be a bit longer than our standard look at a Pentium 4 heatsink, so let's get going!

The basic idea behind the Zalman CNPS5700D-cu is a simple one. The fan is oriented upside down so air is drawn up though the base of the heatsink, up through the copper fins and then into the fan which exhausts the now warm air out via a custom plastic air duct.

The air duct swivels, and the idea is to direct it towards the closest case exhaust fan. This way, the warm air which is being exhausted from the heatsink is immediately sucked out by the nearest case fan instead of just being expelled into the case and warming up everything else.

The processor produces by far the lions share of heat in a case so not adding 100% of that thermal energy to the ambient case environment is a great way to lower thermals.

We also discovered during thermal testing that the air duct adds a small boost to cooling performance. This is possibly because the warm air is immediately directed away from the heatsink, leaving little opportunity for it to be sucked back towards the intake side of the system.

The difference was only about 0.3 degrees Celsius in our tests (with the air duct on, and then removed), but it is worth noting since we first thought the air duct would actually decrease the effectiveness of the heatsink by a little.

There are three sets of screws around the outside of the air duct which hold it in position. By loosening these screws you can then swivel the air duct into the correct orientation towards the closest rear exhaust fan. You do not want to direct this air duct towards the front of the case as this will disrupt the airflow of the case. Directing the duct right up against a power supply intake fan may or may not work right.

The effectiveness of the system partially depends on the speed of the exhaust fan, and the resistance between it and the duct. In the case of a lower power supply fan, it may not physically be capable of taking in the full flow from the Zalman CNPS5700D-Cu. If the duct is right up against the power supply casing this type of situation could cause back pressure issues which would impact on the effectiveness of the heatsink itself.

A good rear case fan (obviously vents in the rear of the case are not going to work as well) is the best bet, and that is what the air duct should be aimed towards. Now, We dropped the Zalman CNPS5700D-Cu into a average Antec mid-tower white box and it didn't fit completely...