Cool as ICE
Cooling the SP35P2's CPU is Shuttle's venerable ICE heatsink, which has essentially maintained the same design since the P-series chassis was introduced years ago. The cooler's heatpipes and towering radiator wall can actually be traced back to the coolers used in Shuttle's earlier G-series chassis.

The ICE cooler hardly needs an update, though. Cool air is drawn in from the left-hand side of the chassis and blown over the radiator wall before it's expelled from the case with a little help from a 60mm fan mounted directly to the heatsink. In the SP35P2, this exhaust air also blows over the heatsink covering the motherboard's power regulation circuitry before it finally exits the case through generous side vents.

Attaching the cooler to the motherboard requires a screwdriver, but it's a pretty simple affair. The screws are also tapped so you can't overtighten them.

Beneath the heatsink we find a copper base with four heatpipes snaking out to the radiator wall. The fan is powered by a four-pin header that enables linear fan speed ramping. This capability allows the fan to ramp RPMs smoothly rather than annoyingly oscillating between high and low speed settings.

Shuttle's XPCs have always been the quietest small form factor systems on the market, and the SP35P2 is no exception. That should be expected, of course, since the system doesn't introduce any new active cooling elements. Only the motherboard's passive heatpipe cooler is new, and it doesn't make any noise at all. Overall, the SP35P2 maintains noise levels comparable to those of my largely silent workstation, which sits inside an Antec Sonata II enclosure.

XPC Tools
One of the keys to the SP35P2's relative silence is the system's excellent fan speed control mechanism. There are three groups of fans in total: one to handle intake, one for exhaust, and a third set that blows air over the hard drives.

These fans, in addition to system temperatures and voltages, can all be monitored with Shuttle's XPC Tools software. Curiously, though, the version of XPC Tools that came with our SP35P2 didn't report a motherboard temperature.

Unlike the hardware monitoring utilities bundled with some motherboards, XPC Tools uses a simple interface that focuses more on fan speed control than overclocking or other tasks. Users can control all sorts of fan speed control variables, including how aggressively fan speeds ramp and at which temperatures.

Overclocking almost feels like an afterthought here, with users only given control over the front-side bus speed. Control over the CPU multiplier and system voltages isn't provided, despite the fact that it looks like the latter could be supported by the app.