MaximumPC 2006 03

WATER-COOLING

For our water-cooling adventure, we busted

out Koolance’s outstanding Exos 2 external

cooling kit from the nether regions of the

Lab, and then pushed the kit to its limits. The

Exos 2 boasts dual 12cm fans blowing over

a radiator the same size, and it’s capable of

outstanding cooling performance. We turned

the fans to full-speed for testing in order to

ensure maximum cooling ability. Though we

were able to achieve an extra 300MHz over-

clock—to 4.44GHz—this CPU was just as hot

as using water as it was using air-cooling,

registering full-load temperatures higher than

80 C. That’s damn hot for a water-cooled

setup, but this is the game of overclocking.

If you want to ratchet up the clock speeds—

1000MHz in this example—be prepared for

some seriously hot CPU temperatures.

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AIR-COOLING

We actually used two coolers for our air-cooling tests: Zalman’s

CNPS 9500 LED and Cooler Master’s Hyper 6+. Both coolers

received a 10 verdict and a Kick Ass award from us last year, and

are the crème de la crème of aftermarket heatsinks.

We started out with the Zalman, but when we saw temps run

up into the 80 C range, we switched to the Hyper 6+ to verify the

numbers. Our readings were confi rmed. Sure, we were running at

4.1GHz—700MHz higher than stock—but we were still surprised to

see idle temps of 60 C and load temps in the 80 C range. That’s stu-

pid-hot, and much hotter than we would ever want to run a proces-

sor on a daily basis. Amazingly, while the older Prescott CPUs used

to throttle (or slow down internally in order to reduce temperatures)

at 74 C, this new Presler chip slows down only at around 85 C.

It’s amazing we were able to overclock this CPU by more

than 700MHz using just a heatsink/fan, but it was running way

too hot for our tastes.

Lab Tested: Air, Water, and Vapor Phase-Change Coolers

Serious overclocking requires serious cooling. We ran high-end air, water, and phase-change coolers to show

you what can be achieved with various cooling methods

Cooler Master’s Hyper 6+ is a fantastic heatsink, and allowed

us to overclock the hot Pentium by 700MHz. Not too shabby.

Koolance’s Exos 2 external water-cooling unit allowed us to crank up the CPU

another 300MHz over what we could achieve with a heatsink/fan. This is the

power of water-cooling.

An overclocked CPU with a screaming

front-side bus and enough voltage running

through it to electrocute a chicken can get

hot. Very hot. So hot that if you want to

do more than bush-league overclocking,

air-cooling ain’t gonna cut it. Hard-core

overclockers usually choose water-cool-

ing. And if even that’s not cool enough for

you, there’s always ultra-expensive phase-

change cooling. To show you what can be

achieved with each of these cooling set-

ups, we grabbed the best coolers available

in each category, strapped them to our

3.46GHz Presler Pentium Extreme Edition

955, and let ‘er rip.

OverclockingOverclocking

Overclocking