The Prometeia Mach II GT is definitely a product for overclockers at the very top of their game with conventional cooling technologies, but it is still very much a luxury product. Still, as good at it is there is some room for future improvements and revisions here and there. Take the user manual for starters, it is the old nVENTIV version, and it needs some working on...

Temperature measurement in computers has always been an imprecise science. In testing the Mach II GT, we measured the evaporator temperature with a Fluke 54-II digital thermometer from the base of the copper cold head, and compared this figure to the temperature read out on the Mach II GT itself.

The 17°C disparity we saw prompted us to inquire with ECT about how the Mach II GT takes its temperature readings.

ECT responded with a clarification on where its internal cold head temperature sensor is located, and what the temperature on the LCD display actually represents.

The onboard temperature sensor gets its reading from inside the capillary tubing just before the coolant goes into the evaporator. There are a couple of reasons for this. First, according to ECT, that location provides the most accurate reading of the coolant temperature. Second, this temperature reading helps ensure that the Mach II GT's compressor is running within its operational range.

While it's understandable why the temperature sensor is placed as such, from a users perspective the most important value is going to the cold head temperature, as it is this what interfaces with the processor. Please keep in mind that the evaporator temperature is not the exact CPU temperature either. To get that reading, you must use a separate sensor, either via the motherboard or from a dedicated thermocouple.

Short Fuse, Inaccessible Location

In the course of testing the Prometeia Mach II GT, we managed to blow out a fuse when we powered on the test system before the cooler's power reset time had elapsed. Normally when you power the Mach II GT down, it needs a brief period of time (120-180 seconds) before it can safely be restarted. This is counted down on the front panel display, but we unfortunately ignored it. The Prometeia also disables the computer case power switch during this reset countdown, but we used the motherboard's jumper switch instead. Oops, our fault.

Replacing the fuse proved rather tricky as it is wedged awkwardly inside the body of the case. We did manage to get it done after a couple of minutes of struggling with a paper-clip bent at 90 degrees. According to ECT, fuses of between 6.3A and 8A can be used. Should you ever need to, the correct size fuse is 20mm long by 5mm diameter.

Power Consumption

Considering that this type of cooling is based on large electrical motor/compressor, it shouldn't come as a surprise that running the Prometeia Mach II GT will use a lot of electricity. After all, it's basically a refrigerator. With this in mind, we decided to take some power readings to see just how much juice the Mach II GT consumes. We connected the Mach II GT to a Seasonic Power Angel, and here are the results...

When it first starts up, the Prometeia Mach II GT draws 495W of power. That value quickly drops to an idle power draw of about 250W. With an Athlon64 4000+ processor under 100% load, the Prometeia draws slightly more, peaking at the 275W mark. There's no way around the fact Prometeia Mach II GT uses a lot of electricity directly; the motor simply requires it.

Comparing the power usage of the Prometeia Mach II GT to a bar fridge of about 4 cubic feet in size, we saw similar peak results, as the fridge hit a high of 550W when first powered on. Normal power consumption was quite a bit lower though, between 70-85W. The Danfoss NF9FX compressor is usually used in larger appliances like full size fridges, the compressor found in an average bar fridge is about one-third the size. In any case, it is an interesting comparison.