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AMD's FX-8150 further overclocked

The big diesel gets water cooling

You probably know this by now, since it seems pretty much everyone has read our initial review of AMD's FX-8150 processors, but the "Bulldozer" architecture on which the FX chips are based is a "speed demon"—a CPU designed to run naturally at high clock frequencies. The concept is to do relatively less work per clock cycle and to enable higher speeds to make up the difference. You may also know that the FX-8150's performance hasn't entirely lived up to the "FX" product name—or to the expectations of many AMD fans. The reasons for that fact are many, but one of them seems to be fairly clear: Bulldozer-based chips probably haven't reached the clock speeds AMD's engineers originally intended.

We attempted to rectify that fact during our first round of FX CPU testing by cranking up the clock speeds, an effort made easier because all FX-series processors have unlocked multipliers. We were a bit frustrated to find out that we couldn't nudge our chip past 4.4GHz without it turning flaky and crashing on us. However, we also had quite a bit of trepidation about pushing our brand-new, pre-release, 32-nm processor beyond about 1.46V.

Yeah, we were basically being wusses.

We were using a pretty formidable tower cooler at the time, but pumping that much voltage into a chip means it will be thinking deep thoughts about its own mortality before dropping off into C1E sleep. If you're going to push that hard, it's a good idea to have really effective cooling—maybe not just a biggish air cooler, but a truly large water cooling unit, with a radiator the size of Charlie Sheen's liver and a pair of fans to match.

Fortunately, AMD seems to have been thinking along those same lines, because it has been making arrangements to include a beefy FX-branded water cooling unit (originally made by Asetek) in the box with certain FX processors. AMD says it will begin by bundling this cooler "with the AMD FX CPUs in select regions," starting with Japan and "then rolling out into other regions." We don't yet have final word on exactly when this cooler might make it into North America, but we expect the bundle to add about $100 to the price of an FX processor alone.

The cooler is completely self-contained and pre-filled with coolant, so users won't have to mess with filling or maintaining the fluid in the unit. Installing it is as simple as twisting in the four thumbscrews around the CPU socket, making a fan-sandwich out of the radiator, and plugging in a couple of headers on the motherboard. One of those headers powers the pump and fans, and the other is a USB connection for control and monitoring of the cooler. AMD supplies a software CD with a relatively simple utility that monitors the liquid temperature and fan speeds, along with allowing the user to choose one of the pre-existing fan control policies or to define his own.

Our mission was to see how far this fancy bit of kit would allow us to push an FX-8150 processor. At AMD's recommendation, we chose the "Extreme" fan speed preset. Fluid and fan temperatures plummeted as Damage Labs was filled with a loud, Dyson-esque whine...