by johnd - Feb. 19, 2000

with contributions by: Darren Habermehl

Another user has sent in his information about his success with overclocking a PIII 500E, but this time the emphasis is on cooling the CPU. Darren has put together a heatsink/fan combo that has allowed him to reduce his CPU temperature by 10.5 degrees C. This is an inexpensive modification and is detailed below.

Darren's overclocked PIII 500E is running stable at 800Mhz with a 160Mhz FSB speed. His system consists of a BE6-II motherboard flashed with the QJ BIOS, 256MB of Hyundai 7ns RAM, a Quantum KA hard drive, and a GeForce DDR video card.

The PIII 500E FC-PGA coppermine CPU is mounted on an Iwill Slocket II slot one adapter. The stock heatsink has been retained, but the stock fan was replaced. This heatsink/fan combo still allows all the DIMM slots to be used on the BE6-II motherboard. Plus, a side benefit that all of us will like, it also saves money by not having to buy another heatsink. To help with the cooling a Globalwin fan, taken from an old Pentium II cooler, was added to the backside of the Iwill Slocket II slot one adapter.

Settings

The Iwill Slocket II was set to 1.6v, the default for a PIII 500E. Also, the FSB jumper was set to "Auto" on the Slocket II. The BIOS in the BE6-II was set with the following settings: Que Depth 1; AGP 1X, Memory 3,3,3, FSB 160Mhz. He found after swapping his DIMM around in the three available slots that it worked best in slot 3.

Assembly

The bottom of the stock heatsink was lapped, ie. it was sanded it on a flat surface to produce a smooth flat surface. This maximizes the surface area in contact with the PIII chip. Three holes were drilled in the heatsink. {See the picture below.} The holes were drilled in steps starting with a 1/16 inch hole. Larger holes were progressively drilled until the hole diameter reached 1/4 inch. This was done to prevent any damage to the the heatsink fins. Darren recommends using a drill press for this step. {Note: The three holes were drilled in the stock aluminum heat sink with the intent of adding more surface area, but after discussing this with Darren he agreed that the area of the holes in effect removed more surface area than the edges of the holes contributed. However, the holes may allow for increased air flow through the heat sink.}

The original stock fan was replaced with the largest fan Darren could find that did not interfere with the first DIMM slot on the BE6-II motherboard. He found a Sunon #KD1206PTB2 60mm x 25mm fan for $8 at a nearby electronics shop. The fan was attached to the heatsink using 8/32 machine screws.

The Iwill Slocket II was opened by gently prying on each end to snap it apart. A hole was drilled in the center of the back cover using a 2 inch diameter wood type hole saw. Three additional 5/16 inch holes were drilled on each end of the back cover to allow for air flow. A GlobalWin fan from an old Pentium II was tapped with a 10/24 tap. Then four button head screws were screwed into the fan assembly from the inside of the back cover. The Iwill Slocket II was then snapped back together. The stock heatsink/Sunon fan combo was then mounted on the CPU.

Results

Before any modifications, the temperature on the CPU ran between 102 to 106 degrees F (8.8 to 41.1 degrees C). After the modifications, the CPU maintains a temperature between 84 and 86 degrees F (28.9 to 30.0 degrees C). This is after running hours of Unreal Tournament. While running the PIII 500E at 800Mhz, SiSoft Sandra produced a score of 2170 mips.

Conclusions

Overclockers are always coming up with ways to cool their overclocked components. The solution provided here by Darren is another fine example of the inventiveness that is alive in the overclocking community. This solution is not an expensive one and with a little care, some spare parts, and a little skill with a drill, it can be duplicated for your system also.