Shuttle SB86i BTX SFF system

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The stock "Thermal Module" that the system ships with is quite a beast, both in size and weight. Given that it draws its air from outside the case it should have no problem cooling even the hottest Prescott CPUs. The whole module weights upwards of one kilogram and includes a 92 x 38 mm fan. It's a good thing Intel has revised the recommended heatsink weight to 1 kg for BTX! A metal backplate is supplied to ensure that the weight of the heatsink does not crack or warp the motherboard.

Intel's "Thermal Module" consists of a PWM-controlled fan, a large heatsink, and a plastic duct.

Flipping the Thermal Module over reveals a small, polished copper contact surface that extends up through the heatsink.

The edge of the fan hangs below the heatsink.

The position of the fan is quite unusual for a heatsink; in fact, it would be impossible to mount the Thermal Module in an ATX-based system. The reason is that the bottom of the fan extends past the bottom of the heatsink, and would interfere with the motherboard in an ATX system. In a BTX system it hangs over the edge of the motherboard and provides a small amount of airflow under the motherboard, and an even smaller amount between the motherboard and the heatsink. As you can see in the photo blow, the voltage regulator components around the CPU socket also get airflow from the HSF.

The motherboard stops before the edge of the case, leaving room for the fan to blow air under the motherboard.

There is ~4 cm between the front of the motherboard and the front of the case.

The stock fan is quite large. At 92mm, it is nearly half the height of the whole system, and its 38mm depth should generate more air pressure than a standard 25mm thick model could. It is clear that this fan is intended to cool the whole case, not just the CPU. At a nominal 12V, it's rated for a whopping 0.88A — that's an 11W draw for a fan. Fortunately, the fan is PWM controlled and is not intended to run at full speed except in case of emergency.

The fan is Intel branded, but it's made by Nidec.

The heatsink is easily detached from the plastic duct by lifting two plastic clips. The design of the heatsink is quite unusual. The copper base that makes contact with the CPU extends upwards into a thick-walled cylinder for the full height of the heatsink, transferring the heat it carries to the "fins", which is (are?) basically a coil of thin aluminum friction-fitted around the cylinder. Given the sheer mass and surface area of the heatsink, it would be quite an engineering stumble if this heatsink and the powerful fan did not perform well enough to cool the the CPU. However, the spacing between the "fins" looks a bit tight for good low airflow cooling.

The heatsink is a spiral of aluminum coiled around a copper core.
It is a slick piece of value engineering; surely it's a lot cheaper than more conventional machined HS.

Installation of the thermal module is straightforward: Apply thermal interface material, place the Thermal Module on top (carefully — it's heavy), and tighten the four screws until they stop. The only caveat is that a screwdriver with a short shank cannot be used; the screws are in recessed holes and the shape of the Thermal Module prevents the use of a nonstandard screwdriver.

The screws are not spring-loaded, so correct contact tension depends on the correct positioning and height of the motherboard relative to the bottom of the case. No problems related to contact tension surfaced during our testing.


As mentioned, the power supply is a 275W model that conforms to the CFX form factor that is specifically designed for use in SFF systems. Ventilation through the unit appears to be fairly good, an important factor if it is to play a role in exhausting heat from the case. An 80mm fan with a fairly unrestrictive stamped grill provides airflow through the unit.

No testing was done on the unit, but the young age of the CFX form factor makes us optimistic that it can perform on par with modern power supplies.

Specifications for Hipro Power Supply model HP-Q2757F3P Rev. X04
AC Input
100 - 127 V / 200 - 240 V @ 47~63 Hz
DC Output
Max Power
Total Power

275W is a little on the small side for a full P4-based system, but in a SFF system where the number of additional devices is limited it should be just about right. One thing to notice would be that it does not appear to fully support PCI-Express. Not only does it lack the standard 6-pin connector for auxiliary PCIe power, it does not have enough power on its +12V1 rail to support the 75W that PCI-Express is rated for.

We do not see a lack of full PCIe express as a serious drawback. Adding a VGA card that draws enough power to require an additional power cable to a system of this size is a recipe for heat-induced problems.

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