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Review: Asetek VapoChill XE

by Ryszard Sommefeldt on 23 August 2003, 00:00 4.5

Tags: Asetek

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VapoChill XE

Tarinder covered the VapoChill PE back in September of 2002, nearly a year ago. The PE, or Premium Edition, was the 2nd generation of VapoChill systems, along with the SE as it's now known and sold, and the original version is now known as the Classic, the first generation of Asetek's chiller units.

It's the 3rd iteration of the 2nd generation of VapoChill that I'm looking at today, the XE. XE, as you've no doubt guessed, stands for Xtreme Edition. What makes it so extreme, when compared to SE or PE?

The original SE model used a Danfoss BD35 12-volt compressor in its chiller assembly. The BD35 is a commercial 12/24V compresser that Danfoss sell for use in a massive range of refrigeration scenarios. R134a is the refrigerant liquid used in the SE with the BD35. Danfoss's PDF datasheets for a BD35 in 12-volt operation with R134a seems to suggest a minimum temperature of -30 celcius, at a load of 26W with a 3500rpm fan. That's an ideal temperature, given that no current processor produces a 26W load (it's usually a lot more) and if it does, it's got no real usage underneath a VapoChill!

The PE model swapped to a BD50F compressor, again from Danfoss, and again with R134a as the refrigerant. The BD50F is a more powerful compressor (it uses a bigger compressor cylinder), and hence achieves a lower temperature by allowing faster refrigerant flow around the system.

The XE goes back to the BD35 compressor, but swaps refrigerant from R134a to R404a. Danfoss don't actually spec the BD35 (or any B-series compressor) with R404a, so it seems Asetek do the modification themselves. R404a gives the BD35 the ability to remove 180W of heat from the cooled site (your CPU), versus ~135W for a R134a equipped BD35 SE model. It's a higher capacity refrigerant and can therefore remove more heat from a system than R134a.

In comparison, Chip-Con's Prometeia Mach II system has a 200W capacity, giving it a slight edge in cooling performance. But 180W is more than enough for todays CPU's, even overclocked, at the expense of a slightly lower final temperature compared to an XE VapoChill unit.

It's worth noting that Asetek sanction an end user swap of R134a for R404a in BD35 equipped SE's. Take your SE along to an air-conditioning repair shop or other place that can swap coolants in refrigerant systems, and get them to replace the R134a with around 70g of R404a. They sadly don't warranty any converted system. There's a thread on their forums about it here

ChillControl 2

Original VapoChill's, SE and PE included, shipped with first revision ChillControl units. As stated before, the ChillControl is responsible for controlling the operation of the cooling unit and the system as a whole. It regulates startup temperature, operating temperature, compressor fan speed, external fan speed, monitors temperatures and keeps the system from booting until it's being properly cooled.

Original ChillControl units were fine, except they didn't handle 4-pin ATX12 connectors that an increasing amount of motherboards take advantage of. Boards that do use ATX12 connectors, generally use them for CPU power, and certain combinators of power supply and original ChillControl equipped VapoChill's weren't quite compatible. The 12V source to the ATX12 connector, and therefore to the processor, was never held low by the system. A voltage was therefore given to the processor, causing it to heat up rapidly, before the evaporator could do its job.

So a refinement to ChillControl was needed, to handle ATX12 supplies and motherboards. The result is a revised ChillControl, version 2, that has no trouble working with the latest motherboards and power supplies. The ChillControl v2 ships with all new VapoChill's, including all XE's (since it debuts with the XE), and is an upgrade option for owners of v1 equipped units, who don't want to spend money on an entirely new VapoChill, just for compatibility with newer boards and PSU's.

Here's a bare press shot of the new ChillControl.

So we know about gas phase change cooling, we know what VapoChill is and what it looks like, and we know what the XE model is like in terms of specification. What's it actually like to fit one to your system? Asetek shipped me out a Socket A version, I better tell you what it's like to use.