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View Full Version : Air flow Direction on Heatsink Up or Down



Huckleberry
11-29-2001, 02:30 PM
I am working some heat issues out on my system.

Specs.
1.33 GHz AMD Tbird, oc'd to 1.477Ghz, Temp 42-47 c
I currently have the heat sinc fan sucking the hot air up, with and a fan duct(see Pic) right above the cpu that sucks the hot air out of the case.

http://www.directron.com/lib/directron/cool-fun2.jpg

I thought I would try the fan blowing down on to the heat sink to maybe improve the temps, but it quickly rose to 49 so I switched it back.

The main question, What way should the Heat sinc fan be blowing in normal situations.
Obviously in my situation up is better.


Some history with my system if you care to read on.

I purchased the Dragon orb 3 w/7k fan hoping it woul improve my cooling needs, I used Artic Silver ll. I noticed absulutly no improvment in cooling and just alot of noise from the fan.

So I replaced it with my old one ( aluminum fin generic) and Artic Silver ll. I have Purchased some new fans (Thermaltake 60mm 31 CFM @ 4550 RPM, 28 dBA)(not as loud as the Orb3) with some decent air movment, for the heatsink.
And a Sanyo Denki 92x30mm, 55.1 CFM @ 2900 RPM, 36 dBA for the fan duct to suck the hot air out.

I hope this will improve things.

Wiggo
11-29-2001, 02:41 PM
Most are designed to blow into but some (like Alpha) are the other way around but it doesn't hurt to experiment with both ways and see what turns out best as some of the usual ones actually do better the other way. ;)
<center>http://members.optushome.com.au/wiggo100/beerchug.gif</center>

Oldbugger
11-29-2001, 04:04 PM
Laws of physics....each degree you get the case temp down will mean a degree drop in the cpu temp....

obviously your setup is better by clearing the hot exhaust air by sucking rather than blowing.

My system is a 1200 @ 1400 with a fop32-1 (lapped) blowing BUT the power supply vents are close by and exhaust the hot air from the heatsink directly thru the power supply before it can circulate in the case and heat it up.....also have two 40CFM fans ..one sucking fresh in at the front (BIG hole cut in case) and one exhausting also under the power supply....max temp has been 45C with room temp at 25C... I get a 20C differential between ambient and cpu temp under load...at 20C room temp the cpu is at 40C....

It really depends on your hsf design and airflow thru the case to remove hot exhaust air....keep in mind you can only drop the case temp to room temp without active cooling and all the fans in the world will not make any difference if your case temp stays around room temp....

MySTiCuSS
11-29-2001, 09:19 PM
With my computer. One blowing on the cpu, one in front blowing, one sucking after the cpu. With a dragon orb cooler. I got 20 degrees system temp, max 40 degrees cpu.

Dlab
11-30-2001, 04:00 AM
somewhat common with orbs. Like M^ confirmed, where are you getting your T's? If it's a board reading or software, they are notoriously incorrect. I know my MSI runs 5c hi. You maybe alrite.
If it's a T prob, then you have room for improvement. Try ducting in air from outside the case, as long as it isn't air from around the rear of the power supply. This also means you need the hsf blowing the new cool are down.

As for your shim question on the other thread, better check with the maker, most orb's dont like shims.

GL
:D