[ClayMan]

I've been thinking about air cooling alternatives lately. Or more specifically, an alternative to the mammoth noise created by the best fans nowadays. I currently have a Delta 38cfm 60mm monster in my tower, and the 80mm king Tornado I plan to upgrade to apparently sounds similar. Frankly, everybody in the house is tired of the constant whine (and this house isn't that small).

So I was wondering about the theory of mounting extra fans on the side of a heatsink. The goal? Multiple quieter fans hopefully achieving a similar or better result than a single 70dB fan. Does the physics work? How would the cfm's add up? I would probably have the top fan blowing in as usual, and the side fans pulling the hot air out. I know the surface area of contact between air and metal would stay constant, and that there's probably a finite limit when air starts travelling faster than heat can be absorbed to it. But assuming we stay under the limit, how would, say, a 5x25cfm setup compare to a single 80cfm tornado blowing on top?

I know this is not a novel idea (Check out the massive coolers comparison at http://www.dansdata.com/), with unspectacular results. But was this because the heatsink itself sucked at absorbing/dissipating heat, or a flaw in this theory? As in, if I applied this multifan setup to the Thermalright SLK-800 copper mammoth as opposed to a "microplex silent twin," (with say, a tornado on top and a couple thin 60mms on each side) would it get me lower temps?

Of course, we're assuming the fans all fit. I'm just talking theory here.

Sorry about the long post.. I hope someone can shed some light on the confusion that is my mind right now.

[cmcquistion]

A single Panaflo L1A (24 CFM @ 21 dBA) on top of an SLK-800 would cool better than your current cooling and be almost inaudible.

Trust me. I've got 4 SLK-800 with L1A's on them. They are the highest performing heatsinks and fans I have ever used, regardless of noise level or CFM claims.

[typhoonmike]

I am in no way an expert when it comes to this. I'm in fact very clueless. I just find it hard to believe that a fan that puts out 1/4 of the CFM of a Tornado can perform as well or better. Looking at the Panaflo(granted it's just a 2D image on the web), the fan blade angle doesn't look anything out of the ordinary or other fans or anything else.

As I said I really have no clue about this so not trying to argue your statement. Just if you could elaborate some more it would be great. I'm sure many people including myself would love to get comparable perfomance to a Tornado without all the noise and for half the price it seems. And apparently not many people that post here at least know of this fans possible perfomance since many post that they are using a Tornado or something else that's loud with high CFM.

[cmcquistion]

I'm just saying that the L1A performs great on the SLK-800. It isn't the end-all be-all fan of the world. It does not outperform a tornado on the SLK-800, but it does outperform a tornado on other heatsinks.

SLK-800 + Panaflo L1A = very good cooling and very low noise.



I have a dual XP1600 system overclocked to 1800 MHz. It folds proteins 24/7. It has 3 intake L1A's, 2 exaust L1A's, and two SLK-800's with L1A's on them. My full load temp averages are 86F on CPU1, 104F on CPU2 and 73F case temp. I give you average temps, because my computer is at 100% load on both CPU's 24/7 and these are the average temps since the last time I restarted the system, yesterday.

[four4875]

if you're suckin air across the HS faster than it can transfer, you're actually LOSING performance.

[typhoonmike]

Well those temps are much better then what I get with my Thermaltake or with the YS-TECH I had on before it.

[cmcquistion]

Well those temps are much better then what I get with my Thermaltake or with the YS-TECH I had on before it.

They are better than any heatsink I have ever used! That's why I brag about the SLK-800+L1A so much. I have another dually in the other room than is performing great, too. Right now, it only has one CPU in it, while I wait for a new pair, and it is getting 93F CPU temp and 77F case temp. This is full load, of course. That case has two intake and two exhaust. The intakes are L1A's. The exhaust fans are another brand I can't remember at the moment, but they are only 18CFM each.

[typhoonmike]

Well was just searching for that particular fan on the web and noticed that there are other versions of those fans that put out a bit more CFM. You ever tried any of those?

[cmcquistion]

I've never tried any of them, but I just ordered some of the 39.6 CFM models, so I'll give them a shot sometime this week and see how bearable they are. To me, the most important thing is noise. Performance is important, but secondary. So far, I have like the L1A because of it's low noise. I'll probably keep using them for a while. The other models are simply faster models with the same design, so using them on a rheostat to slow them down to lower noise levels, would be equivalent to using an L1A all by itself.

[ClayMan]

Well there's another thread going on about something similar.. But would having a weaker, less powerful fan blowing across the vents perhaps help in solving the backlogging problem?

I know it's probably improbable that the performance of a tornado could be replicated with multiple weaker fans. So just talking thereotically, would extra fans blowing sideways, or perhaps at a slight angle (downwards towards the cpu) help take heat away from the cooler? Or is there some part of physics and heat conduction that i'm completely missing here.

Someone mentioned that having air blow sideways across the vents before it reaches the base of the heatsink may actually decrease performance. Can someone please elaborate? I also noticed that not all 4 sides are vented usually, i.e. on the SLk-800. Look at this picture:


What about having fans blow on/away from the side of the heatsink in the picture there? (the unvented part) Would this help at all? (I know there isn't a lot of surface area..)

[cmcquistion]

I think that maybe having a fan on each side blowing in the vents (maybe a 60mm?) and a top fan blowing up, ~may~ work quite well. Of course, it may make no difference at all, but that would be my choice of mod for the SLK-800 heatsink.


BTW, any multi-fan solution would introduce a lot of air turbulence that would cause additional noise, so it may not be worth it.