The future of high end PC cooling revealed

MANY OF THE INQ's younger readers - especially the teenage gang - might not be aware that, once upon a time, there was such a great, environment-friendly age when even the fastest PC CPUs didn't have any fans.

And not even heat sinks even when running full blast.

Do you still remember those days when, say, 386DX or 486DX model digits, speed and all other numbers - the same for Motorola 68030 on the Mac - could be read off easily from the ceramic CPU package, any time during the operation?

Well, that golden or rather green age ended with Intel's 486DX2. From that point on, the combination of increased number of transistors, clock speed and die size obliterated any semiconductor process and low voltage benefits to rapidly increase the power requirement and resulting heat output on all PC-class CPUs, including the mobile ones. So, for the past two years, whether you're with Intel or AMD, you knew you need to allocate at least 100W, and up to 170W now, for the top-end CPU. With that power, along come some extraordinary heat to remove.

Over that period, CPU cooling devices evolved from simple aluminum heat sinks, to heat sink & fan combos (one of the first was the embedded heat sink & fan on Intel Pentium OverDrive for the 486 socket - see photo), to higher-efficiency full copper heat sink-fan combos with heat pipes and low-noise large fans. Thermaltake, Asus, Zalman and Coolermaster compete in this segment, among others.

Beyond plain air cooling, water cooling came in from supercomputers and mainframes to offer more efficient yet still quite affordable products with generally another 10 degrees C or so lower CPU operating temperature - high-end water cooler vs high-end fan. While these can also take care of chipsets, GPUs, VRMs and even memories or hard disks, the cumbersome installation and leakage problems are still there.

Thermoelectric - TEC (Peltier Junction) CPU coolers like Vigor Monsoon series match the water cooler efficiency without spilling any water, but the TEC operation requires a dedicated power feed for the cooling device, and the failure of the device during the operation is just as dangerous as on the water coolers. I'd personally like some mini-versions of TEC devices for the North Bridge and VRM system areas, where their ability to handle high heat would help quite a bit. Keep in mind their hot-cold plate temperature difference is water condensation risk, no fun for an electricity-laden mobo.

On Intel's recent 65 nm devices - whether it was Pentium XE965, Core 2 Duo or Core 2 Quad in their various "plain vanilla", Extreme and Xeon flavours - I was easily getting anywhere between 25% and 35% clock speed boost for what I'd call "reliable every-day productivity overclocked PC operation" (i.e. something that you can run for at least a year rather than suicide overclocking) when using either high-end fan or water cooler, all that with just up to 4% voltage increase (if any) compared to the default. On 90 nm AM2, the most I could get was around 12% - from 2.8 to 3.1GHz. Hope the 65 nanometre Barcelona parts have better margins.

This is a decent extra performance gain, especially if your FSB and memory scale correspondingly as well - in such case, application performance benefit might just correspond to the clock speed increase. Unless, of course, you're running Windows malware - after all, Vista + Office 2007 may need dual-core CPU and 2 GB RAM just to comfortably type this story, isn't it?

What if we want to go way beyond this CPU performance gain? Maybe something like combined heat exchanger & fan on top the CPU/chipset water block, like Thermaltake's Volcano series? This way, when the water heats up cooling the CPU, it is cooled down right away by a big amount within the heat exchanger tubes and the airflow, so that it is reasonably cooler by the time it goes back to the pump or North Bridge water block.

Alternatively, we could, say, mount an external fridge that cools the tubes of a water cooler system before and after they go through the pump? Hmm, such 'fridge' would have to have pretty tight contact with the tubing (and long section of it) to produce any really useful help. It would be lovely to keep the water temperature at, say, 10 C or so consistently, maybe we get an extra 5% on the CPU speed.

However, there is a more radical, way more efficient and, yes, more risky approach - one that would be loved by "Mr Freeze", the current California governor's incarnation from a Batman movie. How about using a basic kitchen freezer design, change the gases a bit and, instead of cooling 3 pounds of steak or fish at -18 C, cool 1 ounce of CPU at -40 C?

It is nothing new - Kryotech had it working in commercial systems since 1998. Does anyone still remembers "Cool Miata" DEC's famed 64-bit Alpha workstation running at 767 MHz off a quad-issue Alpha processor in that very year? And yes, you could buy it will all the warranty and that. In the same year, a 266 MHz Pentium II was still the high-end of the PC market.

In fact, I had the privilege to assemble and play with both Cool Miata and Kryotech's millenial offering, a 1 GHz Athlon Slot A supercooled setup - both had the same modified freezer design, -40 C CPU operation with roughly 30% default CPU overclock, a very thick pipe with cooling block at the CPU socket or slot, and hell of a lot of trouble insulating it to prevent deadly condensation. The latter problem is especially dangerous in warm environments like here in Singapore, or heater rooms in northern winters.

Talking about northern winters, that's where the current crop of extreme coolers comes from: places like Denmark - remember Extreme Cooling with their famed Mach 2 GT? With that marvellous (and marvellously heavy) box, around -40 C was the order of the day for everyday operation, even with the hottest CPUs. The only problem? No news (or phone number) of the vendor, emails aren't answered and, well, the web page endured over half a year since the last update. Asetek Vapochill, on the other hand, is still a very active and selling product. Asetek themselves is now focusing on 'daisy chain' water cooling systems for one or more CPUs, something that I could use for, say, Clovertown DP, Tigerton, AMD QuadFX or Opteron setups - overclocked quad-socket gaming server, anyone?

Why would Asetek move away to water coolers? Well, for one, freeze-cooling systems have big issues with insulation and prevention of lethal condensation around the CPU, when there is as much as 60 C operational temperature difference between the cold plate on the CPU and the surrounding on the mainboard. The current crop of freeze coolers seem to handle this OK, but the user installation is often the critical step where a failure may occur, like not fixing the insulation elements tightly and so on.

This does affect the freezer vendors' RMA and support load, but again, I believe that, if you want the best overclock without spraying some noxious liquid nitrogen yourself, there is no other way but Mr Freeze.

In summary, with four cores per socket CPUs, burning hot North Bridges, and GPUs that each consume as much power as a 50-inch LCD TV set, we're having hotter-than-even high-end PCs. For a determined "enthusiast" computer fan(atic), the ideal solution would probably be freeze-cooling the CPU with Mach 2 GT or Asetek Vapochill-like device, then water-cooling the glowing-hot North Bridge and VRMs with combined heat sink / water block units using heat exchange (Nforce 680i would surely benefit from this - see Sunday's story) with South Bridge just with a plain water block, sufficient for its heat load.

As for the GPUs, their own immense TDP, especially when in SLI/Crossfire combination, in my opinion requires a separate water cooling system on its own - Asus upcoming R600 solution, or Thermaltake's new dual-GPU water coolers, fit this description, having a single pump/radiator/fan set feeding two cards. All this should still be able to fit within a single tower case, even if you use an 'enhanced' configuration with dual-socket Intel Clovertown or AMD Barcelona setup, for the "lucky eight" cores on your disposal.

Such a system could easily have 40-50% higher CPU speed (at least for Intel stuff), similarly higher FSB to feed the beast, and around 15% GPU clock improvement - not bad, knowing we mean stable operation for a year or two at least. But again, just wait for Micro$oft to announce, say, DirectX 11, and/or an even more bloated successor to Vista, and all this effort goest into the waste grounds of PC obsolescence. Unless, of course, you've ditched Windoze and actually do some work - on Linux. µ