How could we possibly test a phase-change cooler without doing some overclocking? For this section of the review, an AMD Athlon64 4000+ processor (stock speed 2.4GHz) and a DFI LANParty NF4 SLI-DR motherboard were used. It will be interesting to see just how well the Athlon64 4000+ will do with its 1MB of L2 cache....

The first overlocking snag came up at 2.88 GHz (240 MHz motherboard clock speed). The DFI LANParty NF4 SLI-DR system would randomly BSOD while loading Windows, so the CPU voltage was raised to 1.65V to stabilize it.

The overclocking continued until the system ran into some CPU stability problems at 2.96GHz, illustrated by the fact it could not finish a 1 million digit Super Pi test. To solve this, the CPU voltage was increased further still, to 1.75V.

Unfortunately, it seemed our Athlon64 4000+ test processor didn't like high voltages and it maxed out at a speed of 3.06 GHz (255 MHz motherboard speed). It's not the greatest overclock I've *ever seen* with a Prometeia Mach II GT, but we did reach our goal of at least 3 GHz.... and let me tell you, it's fast!

All the while this overclocking was going on, the idle temperatures were sitting at about balmy -24°C according to the BIOS.

Now, according to the ITE Temperature reader which is read by overclocking software when the system is in Windows, the processor was running (incorrectly) at 240°C! The program doesn't know how to register negative temperatures and once you go below zero it starts at 255 and counts downwards. What we were really looking at was a loaded temp of somewhere around -15°C.

Conclusions and Summary

We just finished looking at ECT's flagship phase change cooler, the Prometeia Mach II GT.... and we're pretty darn impressed.

Nothing else on the market can give overclockers such low temperatures with a minimum of fuss or mess. From our staffers position as an owner of both Prometeia and Vapochill coolers, he definitely prefers the ECT way of handling insulation around the CPU socket.

Current Prometeia owners may like to know Mach II GT is virtually identical hardware-wise to the previous generation. The only real difference is the type of refrigerant used in the compressor; that being R404a instead of R134a. The R404a refrigerant allows the Prometeia Mach II GT to reach its booting temperature faster, but more importantly it allows the cooler to attain a lower operating temperature! Compared to the older models, users can expect a drop of -10°C to -15°C.

Acoustically, the ECT Prometeia Mach II GT is in general pretty quiet, but the compressor motor does create an audible low-pitched hum. In most situations this noise will blend into the background, and in quieter environments it will be as disrupting as a bar fridge would be. Yet for the temperatures attainable by the Mach II GT, the noise created by the compressor and two fans is acceptable, and nothing compared to the old standard of a Vantec Tornado or 60mm Delta screamer.

In the overclocking tests conducted with the Prometeia Mach II GT, PCSTATS was able to push an AMD Athlon64 4000+ to over 3 GHz while keeping operational temperatures of -24°C at idle! Load temperatures were in the -15°C range, which is still nice and frosty. During testing, evaporator temperatures hovered between -60°C and -45°C mark, depending on the heat load the Athlon64 4000+ processor was generating.

With a current retail price of $1042 CDN ($849 US) through vendors like Hardwaregods.net, there is no getting around the fact that the ECT Prometeia Mach II GT is a luxury item for dedicated overclocking enthusiasts.

However, if you are thinking about taking the plunge, consider carefully what we have said in this review and remember that ECT have a very flexible cooling system here. It's one that meets the needs of only the most demanding users, but as long as new socket kits are available for future processor releases there is no reason why the Prometeia Mach II GT couldn't be used years down the road. In that respect, as a long term "investment in cooling," it certainly will earn its keep. With dual core processors from AMD and Intel hitting the market, the days of overclocking on air-cooled heatsinks and watercooling rigs are numbered. It's a pretty good bet that processors which are as yet unreleased will continue to generate substantially more heat per square inch, so overclocking hardware will have an increasingly difficult challenge placed before it in the years to come.

Besides all of that, a phase change cooler like the ECT Prometeia Mach II GT is just too damn cool! ;)

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