Reverse airflow on HS fan

BillyBuerger · Post by **BillyBuerger** » Mon Feb 10, 2003 1:41 pm

I'm thinking of doing something similar to Rusty's Quiet In-Desk PC. I plan on having my motherboard horizontal like he has. I was just wondering what the pros and cons are to mounting a fan so that it blows the air away from the HS instead of onto it. My thought is that since you don't see this configuration often, that it probably isn't as efficient. I would be ducting the air out of the back similar to Rusty's again. My difference is that I plan on having the fan directly on top of the HS still.

Thanks

ChiefWeasel · Post by **ChiefWeasel** » Mon Feb 10, 2003 1:48 pm

You're right, you dont see it much - pretty much its only Alpha HSs which perform better with the fan sucking air off it, (because of the shroud they use?). Also if you experiment you will see that turbulence noise is much greater when there is an obstacle on the input side of the fan.

Just try it both ways and see which has the best temp/noise compromise.

TheMuffinMan · Post by **TheMuffinMan** » Mon Feb 10, 2003 2:37 pm

I have an SK-7 and a PC PnC silencer on a 1700+

With the sensor touching the back of the die:
Sucking (air blowing "up" on a horizontal setup) is 2-3 C cooler, but noticeably loud, especially when the fan is at full power (12v).

Blowing (down) is 2-3 C hotter than sucking (note: that sounded very wrong), but the fan makes no percievable noise at medium power (9v).

crg · Post by **crg** » Sat Feb 22, 2003 3:03 pm

BillyBuerger, my new Dell 3.06 ghz and old 1.7ghz both have a similair kind of fan shroud. I have not done any temp tests so all that I can tell you is that the air than blows out of the case fan (attached to the shroud) is much warmer compared to the power supply fan which is cool. It seems to work nicely, but as ChiefWeasel noted the turbulence noise is greater than without the shroud.