Alpha PEP66

3/13/00: Lyle Wong sent in this note on the PEP 66:

I got my new PEP66 from Millisec this AM and had to try it out. I currently have a C433 on an Iwill Slocket 2 and an Abit BF6. I was using the PAL6035, and it blocked two DIMM slots real good. I’ve been running this at 605 (93mhz FSB) at 2.1V, and using Jouni Vuario’s Stability Test, my CPU temps were at 34-35 deg C after four hours. After I put the PEP66 on, I got back one DIMM slot, and my temps are now at 32-33 deg C after three hours. I’m still at 605 at 2.1V because I haven’t had time to play with this yet and I’m still running the test. Temperature readings were taken from Motherboard Monitor.

I did not have to remove the feet to mount it on my Celeron, and the offset clip did not cause the heatsink to rock or tilt. This is fine with me because eventually the Celery will be replaced with a FC-PGA processor.

This is a nice unit, and if all it does is lower my temps by a couple of degrees, well that’s fine with me.


PC NUT was kind enough to send us a sample of Alpha’s latest – the PEP66. This is specifically designed for Coppermines and I tested it against the Thermaltake Golden Orb. As the picture below shows, the Alpha also continues to be one of the largest heatsinks around; the PEP66 measures 2 7/16 x 2 7/16 x 3 7/16 (62mm x 62mm x 89mm). This is another DIMM slot blocker on space-constrained motherboards.

Two Sinks

The base is quite a piece of engineering – a copper insert (a la PAL6035) but the PEP66 sports plastic lugs to ensure level mounting. CuMine mounting is critical considering the CPU’s diminutive contact area and Alpha’s solution works very well. The mounting clip is properly off-center and is very easy to engage and disengage. As usual, Alpha suggests mounting the fan so that it sucks air through the fins and exhausts out the top; this can also help to cool the board’s chipset resting under the Alpha.

The base also features two indentations – one for the socket’s ramp and one for the lever – this is the first heatsink I have seen with this design. This is a nice touch – no need to bend metal arms to get it to fit. The clip is also a little different – it features a curve which is needed due to the Alpha’s overhang – it extends slightly beyond the lugs. Attention to detail is one of the hallmarks of Alpha designs.


Note the nylon feet – they are designed to align the PEP66 on CuMines.

There are plenty of fins (88) sporting an aerodynamic shape, as shown below. A shroud covers the fins to direct air through them. The Alpha comes disassembled but the directions are quite clear – all it takes are four screws to attach the shroud and four long screws for the fan. The whole assembly weighs in at ¾ pound (300 grams).


The inset shows the fins’ shape – very aerodynamic.

For this test, I used my CuMine 500E @ 667 MHz on a cheapo slotket ($10 – no voltage adjustments).


The Alpha blows out – could help cool the chipset.


I ran Prime 95 until temps stabilized, then recorded 500 one-second samples using Motherboard Monitor. I wanted to see how well the Alpha would do against the Golden Orb so I ran it at the same time for a comparison; results are presented below:

PIII @ 667 MHz   
HeatsinkLow TempHigh TempAverage Temp
Alpha PEP 6627 C29 C28.0 C
Termaltake Golden Orb29 C30 C29.9 C

Ambient Temp 20 C, System Temp 22 C.


The PEP66 turns out to be a fine performer, besting the Golden Orb by about 2 C. The fan I used was a YS Tech 26 cfm so it was not quiet – performance has it price. In sum the best CuMine air-cooled solution available. It will make more of a difference compared to the Intel OEM unit than others and may get CuMines “on the edge” over the hump.

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