weird PEP66 vs. Volcano 2 results

[Dill]

I did a lil heatsink testing today...my V2 which came with my cpu against my modified PEP66 that I used on my old P3. AS 2 was used on both HSF's, on my AXIA 9 (blah) at 1400 mhz

the PEP66 has been lapped and I turned the shroud around into a few different configurations for testing, the fan that came on my V2 was used (as it feels stronger than the Sunon that came on the PEP66).

first I tried it with the fan on top, sucking out towards the side cover, result was 61C at full load with RC5
then I had the fan pointing towards the top of the case, sucking out, result was 55C at full load with RC5
I switched the fan to blowing in with it blowing towards the bottom of the case, with no noticeable affect on temp.

then I threw on my V2 and did some testing with it also...
55C at full load with RC5...derr..


I was under the impression the PEP66 should smoke the V2..unless the PEP66 only works well with a Delta black label fan?

 

[nmos]

Why did you lap the PEP66? Every one I've seen has had a surface that was at least as good if not better than what most people could get from lapping. Is the copper inlay still intact? How about with the fan pointing down toward the CPU? I like to "complete" the shroud with packing or duct (actually the "Duck" brand) tape when I use a fan on top of a PEP66.

 

[Dill]

basically to get rid of the plastic feet...the copper inlay is totally intact still. I haven't tried it with the fan facing straight down at the CPU, I'll do that next.

do you have any pics of how you did your PEP66?

 

[eLiu]

uhh...quick thought: lapping is only so good. After a certain point, over-lapping will have NEGATIVE effects on heat conductivity...(article is at www.overclockers.com)

-eric

 

[Dill]

it hasn't been lapped very much at all..just enough to get the plastic feet off. Anyways, I guess I'll putz around with it some more.

 

[Soccerman]

the PEP66 performance does not differ much when blowing or sucking (REALLY). the difference is on the order of 0.01 Degrees C/Watt. The only improvement would be whether or not the air that is being sucked in is warmer or cooler in the different situations (if the fan sucks air off the heatsink, it cannot add it's own heat to the heatsink for example).

as for other configurations (side or top mounted), it's tough to figure out for me, because you need to take alot of things into account (pressure drop due to the fin's curvature when air travels over them like wings for example).

Also, you have to take into account airflow in the case, it is probably best to have the intake facing towards the bottom, and the exhaust taking the quickest path out (reducing the number of devices it has to pass by is key).

This is why I have my PEP66 with the intake facing down (towards the cards in the case), and the fan blowing air towards the case siding (guided by a tube I made going out a hole in the case side).

it would be nice if I could fit the fan on the 'side' sucking air out of the heatsink to the top of the case, but it doesn't fit that way on my motherboard with the power supply in the way.

 

[PlatinumGold]

soccerman

under ideal test conditions like some of these reviews sites use i'd agree w/ u, w/ most coolers sucking and blowing really doesn't make any difference.

but in the real world, that isn't the case, depending on how the air flows in that particular case will determine whether sucking or blowing will perform better and sometimes by quite a bit.