dave@galaxia.Newport.RI.US (News Administrator) (08/06/90)
I have a 7300/3b1 and am trying to determine what the best possible fan configuration is to keep the thing cooled. My current hardware configuration is the following: - 7300 style case (no hump) - 3b1 power supply - 2 meg memory board (no other expansion boards) - two hard disks in case (both ST-251) - two floppy drives in external case (thanks Gil!!) The possible fan configurations that I have come up with are as follows: - two fans blowing out (default config for 7300) - one fan blowing out (default for 3b1??) - two fans blowing in (has anyone tried this?) - one fan blowing in - one fan blowing out and one fan blowing in I am currently running with one fan blowing in (at the power supply) and one fan blowing out and it seems to be keeping the machine fairly cool. I currently have a piece of screening over the fan opening to keep dirt out but I will probably switch to a piece of filter material as soon as I get a chance. Can anybody think of any problems that might result from having the fan blow in instead of out? Also, would any of the other possible configurations provide better cooling? Would it be better to have the intake fan on the side away from the power supply? Something else that just occurred to me is that I have the 2meg memory board installed in the slot under the power supply. Would it be better to move it to the other side of the machine or doesn't it make any difference. -- David H. Brierley Home: dave@galaxia.Newport.RI.US Work: dhb@quahog.ssd.ray.com Be excellent to each other.
yarvin-norman@cs.yale.edu (Norman Yarvin) (08/06/90)
In article <993@galaxia.Newport.RI.US> dave@galaxia.Newport.RI.US writes: >I have a 7300/3b1 and am trying to determine what the best possible fan >configuration is to keep the thing cooled. > >The possible fan configurations that I have come up with are as follows: > > - two fans blowing out (default config for 7300) > - one fan blowing out (default for 3b1??) The default for the 3b1 is indeed a single fan on the power supply side. Supposedly a normal machine is best cooled by one fan only; for your double-hard-drive machine two fans might be better. I have run my machine with two fans and with one; with two fans most of the heat exits out the power supply side anyway. >I am currently running with one fan blowing in (at the power supply) and >one fan blowing out and it seems to be keeping the machine fairly cool. The power supply is a large (the main?) source of heat in the computer. Your configuration blows air directly over the power supply, cooling it, but then that hot air is forced through the rest of the computer. Also, with fans blowing out, air is drawn through the lower part of the computer; if the upper part of the computer has one fan blowing in and one blowing out, there is presumably less of this. Inward-pointing fans also have the disadvantage that they dissipate the heat produced by the fan into the computer. Also, a one-inward, one-outward scheme will push about one fan's worth of air through the computer. (It will blow a bit more than one fan's worth, because two fans halves the drag per fan.) > Would it be better to have the >intake fan on the side away from the power supply? Probably the best way of increasing cooling is to replace the fans with higher-volume ones. I have done this, and the air out of my computer is significantly cooler. Higher-volume fans make more noise, though. -- Norman Yarvin yarvin-norman@cs.yale.edu