This might seem a little odd as instinct seems to suggest placing such sensors directly above the GPU core, or just adjacent to it. After factoring in the option of drilling tiny little holes for the type-K thermocouple everywhere, and the multitude of stock heatsinks we could possibly be contending with, not to mention differing types of BGA packages, simplicity reigned supreme.

Throughout this series of reviews on videocard BGA coolers, we will be taking temperature measurements with a Type-K thermocouple placed directly behind the core, effectively measuring the temperature of that small patch of PCB.

The thermocouple is insulated against the surrounding environment with a small section of closed-cell foam. The foam helps to ensure that the thermocouple stays put, and isn't cooled off by exhaust air eminating from the processors heatsink, case fans, or any other transient sources. To generate some heat in the actual GPU, we found that running 3DMark 2001 three or four times in a row nets fairly consistent results.

We've also included a set of results with a 4000RPM 92mm case fan blowing in the direction of the Zalman ZM50-HP (simulating a front case fan which is common on most computer enclosures) from five inches away. This fan does create a small amount of noise, but as the ZM50-HP does not ship with any fans, the results are mainly intended as an example of what active cooling could bring to the table.

As we can see from the thermal results, with a stock heatsink fan combo the MX440 gets modestly warm. With the passively cooled Zalman ZM50-HP temperatures are bound to rise, and they do to about 58 degrees celsius. As we have seen with the ZM80A-HP, the addition of a slight breeze from a case fan can really change things around - in this case to less than the temperatures we saw with the videocards original active heatsink.

However, it is worth mentioning that in situations where fans are not practical, or where noise is an issue the ZM50-HP works to keep the GPU from completely overheating. Temperatures are going to be higher, and it is a good idea to have a well ventilated case to. As well made as the ZM50-HP is, it seems unlikely that it will see the same level of demand that the ZM80A-HP is seeing.... In any event, the extruded heatsink and heatpipe cooler was easy enough to assemble, and by bending the rules a little and adding a low RPM case fan we were able to net a positive thermal enhancement. If you want to be completely fan free, good ventilation will be important.

Bottom line, a very innovative heatsink which doesn't take up an extra PCI slot, though I'm left wondering why the rear heatsink wasn't equipped with slightly larger fins.