Say what you will about Thermalright, but the company listens to its fans. The low-profile AXP-100R down-draft heatsink wouldn't fit on certain high-end motherboard with tall heatsinks on their voltage regulators. Unwilling to leave a market un-served, Thermalright now offers the AXP-100H Muscle, which is a quarter-inch (7 mm) taller than the previous version.
The increased height and a swap from a red fan to a neutral white one are the only changes in the AXP-100H Muscle when compared to its predecessor. Of course, it's possible Thermalright simply isn't fixing what wasn't broken. Like the AXP-100R, the 100H Muscle is an all-aluminum CPU heatsink with a laterally-mounted fin stack. A specialized 100-mm fan blows down through the radiator, passing air over the sensitive motherboard circuitry below. Six 6-mm aluminum heatpipes connect the thick base to the fins, and Thermalright includes a pair of small posts to keep the heatsink from buckling under its own weight.
Due to the height increase, the new cooler is 2.28" (65 mm) tall with the fan installed. That makes it a bit of a stretch to call it "low profile"—it won't fit in a Silverstone SG13, for example—but it's certainly shorter than a 100-mm tower cooler. While it hasn't appeared on American shores yet, PC-Cooling.de has the new AXP-100H Muscle for 40€, or $42.51.