Air Cooling: Orientation & Monitoring

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ObscureTerror

Limp Gawd
Joined
Aug 29, 2007
Messages
145
Simple question I'm curious about, as I've heard differing opinions.

CPU Cooling & Sink
Is it better to have a fan pulling heat off the CPU, or blowing on the CPU?

Just ordered a new (also as in just released) cooler, the Scythe ZIPANG which is a "top-down" cooler. So the fan is facing the CPU/mobo. Would it just be blowing warm case air on the CPU/mobo? Would it cool better to have it blowing off the CPU?

I've been running the Ultra 120 Extreme, and while I have great temps, the thing is just ridiculous in size (height) and not seated well (it can be easily turned when mounted), which most people already have known about. I have a large case as well (the new Antec 1200) but cant fit a side fan on due to the Ultra 120 either.

The fan on the Ultra 120 blows through the sink and not onto the CPU and it still cools great, so I'm wondering if pulling air directly off the sink would be even better, the having the exhausting fans just pulling it out. Or if I should having it blowing onto the CPU.

Side Fan & Case/GPU Cooling
Speaking of side fans... right now I'm not running one, and haven't in a while. I run an 8800GTX, but modded the HR-03 sink on there with a 120mm fan, which has kept it cool.

However, I plan on moving to the GTX 280 and using it's stock fan, until they come out with an aftermarket cooler that will work well with it and it's not a nightmare to change-out, so: should I have a side fan blowing on the GPU or pulling air out of the case/off the GPU?

In this case, the PSU sits upside-down on the bottom of the case and the GPU above it about only five inches or so, which pushes hot air through the PSU. Right now it's not that bad, but the heat off the new GTX 280 might be pushing it; perhaps even now it is, I'm not sure.

Where the side fan is, it would (or should) pull the hot air from out directly in-between the PSU and GPU, if I have it exhausting.

Temp Monitoring
I rely strictly on RightMark for monitoring my C2D temps. I've always known it to be top-notch at being accurate, but can anyone verify it's accuracy/reliability?

General
I've seen a lot of varying opinions on the best way to use air cooling, and am curious how I should orientate the new set-up. Right now, the only intakes I'm using are the three front 120mm fans. Exhaust, two 120mm rear fans, a top 200mm fan and a side fan that is currently not installed in this particular case. When I can fit it in (soon, with the new CPU sink) I'm not sure if I should exhaust or intake.

Thoughts/info/opinions?

Thanks & Cheers.
 
You can obviously test a few of these questions you have but almost certainly you will get better results with CPU fan blowing down over the motherboard. In general this is always how heatinks get tested and marketed... back in the day it was Alpha that had the ONE cooler that had fan sucking off the heatsink. Since then I'm not sure if I've ever seen a heatsink that used fans to pull air through it rather than push.

Almost certainly the heatsink will perform better with fan pushing air through it.

The onboard components around the socket will almost certainly recieve more airflow with fan pointed down rather than up.

The issue about the air being wamer as it exits the heatsink, although true, doesn't matter all that much. If the fan is sucking air up the components around the CPU will recieve very little air. If the fan blows down they wil recieve much more air that is just slightly warmer. It shouldn't really matter if the air is 30 or 31C when its trying to cool a component that is 70C for example.

As for case fan setup you basically want equal intake out exhaust. Right now in the top compartment of the case you have two 120mm intakes and 2 120mm exhausts and 1 200mm exhaust... sounds as though the side panel would be better off being intake to maintain balance.

The only other thing to think about is video card coolers can either exhaust their heat out the base of th case, which is great, or as many aftermarket coolers do they can dump the heat into the case. While many aftermarkets are great at cooling GPU better they are annoying that they just dump heat into case. I ended up using stock 8800GTS-512 heatsink from EVGA over Accelero S1 as althought he Accelero cooled MUCH better... I ended up having to have much more case air flow to make up for the 150watts of heat it dumped into the case.
 
Excellent response, thanks!

Absolutely, I'll be testing different orientations out, as I always have. I guess I only just recently started really thinking about "optimizing" air cooling as much as possible, as well as the issue of CPU cooling.

In a way, though, the tower CPU sinks usually have the fans blowing through the cooler, so they're neither blowing on the CPU or the mobo. Yet, they still manage to cool pretty well, if not very well. I guess that's what got me thinking that, since those set ups aren't actually blowing onto the CPU/mobo directly, then would it be any different pulling off the CPU/mobo directly anyway.

But I completely understand what you're saying, and I agree, having the airflow directly on the CPU and mobo/components is definitely the best way.

I actually have three 120mm fans in the front, but despite that intake, the two 120mm exhaust in the back and the 200mm fan on the top, my ambient temps are still around the 42-45C mark, which I feel is a bit high.

Of course, I've had the (very nice, actually) speed-controlled fans on low in the back and on the top, but have just put them on medium (and still not loud! Antec makes some good fans here, apparently) and I'll see if that temp drops.

That's one reason I was thinking of using the side fan as exhaust, but then again, more air blowing onto components cools better from that perspective, so you're probably right-on there and it should be intake.

You know, I never really realized that most of the air from stock GPU coolers was exhausted out the back of the case. I always thought it was equally pushed downwards into the case from the small GPU fans. I guess that's not actually the case? From what you described about your situation, I'd say not, and that they do actually exhaust more out the back than pushing down into the case.

If you have any other feedback, please drop another post... this was very helpful, thank you.
 
Well I guess Stock GPU coolers vary. 8800GT, the single slot cooler, dumps it in the case. The 8800GTS-512 has a 2 slot cooler that dumps all the heat out the back. Quadro 5600 is a 2 slot that dumps it all out the back. GX2 dumps heat both out the back and in the case... just feeling with my hand I can't tell where most of the airflow is exiting the cooler. 9800GTX is out the back. I dont' have a 260/280 to look at. Aftermarkets still really destory the stock coolers in performance but none that I know dump out the back. Just another tradeoff to make between performance/oc and maybe noise... I mean you can always just get bigger case fans to push any heat out you want.

Also you're right about case I got it semi-confused with P180 design that has a seperate chamer in the bottom. I guess you'd have 3 120 intakes, 2 120 exhausts 1 200 exhaust and PSU exhaust. Not sure how much air really moves through the PSU. In general I think a balance between intake and exhaust works best but if its real close you can probably try both in and out for the side panel just in case.
 
Yeah, there's nothing like aftermarket coolers, certainly. Either way, hot air will be blowing into the case from a GPU to some degree, generally.

Since this case has the PSU on the bottom and the GPU fan is blowing right into the PSU fan (which only has one fan on it; Corsair HX620) I think it's making it hotter. Feels a bit hotter to me, which is why I was considering having the side fan as exhaust, to maybe suck out some of the hot air from the GPU before it hits the PSU.

I could do it intake, which moves more air around, but since it's hot in the house, I figured it'd just be blowing in more hot air. If the PSU wasn't on the bottom, I'd just use the side as intake, as to have more cooling on the GPU (which I'd prefer to/usually do), but with the GPU blowing into the PSU, I might have to cool some of that off and haven't been sure what would be better, intake or exhaust.

This case is fantastic, but the GPU blowing into the PSU has had me a little concerned about the PSU's temp (it's not moving that much air) and how I can lessen some of that heat. This was really my only other "concern" other than the orientation of the new CPU sink/fan.
 
I recently changed the fan on my intel stock heatsink, it def works better blowing air than sucking it out

If your not using any other cards 92mm fans slot perfectly between the floor of your mobo and the bottom of the vid card, one of these in the corner sucking air out works wonders.

I reckon you could probably score and punchout an 80mm x 80mm square on the 88/98's stock shroud near the cpu and place and screw an 80mm fan directly to the sink sucking air, that would work as good as an aftermarket cool easily
 
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