The 8500s main fan I believe draws air in from the bottom sides' vents, and out the back.
I also noticed while testing, that the temperature spikes when the machine is turned off ... which makes sense ... the fans go off, and the drive needs time to dissipate its built-up heat.
My two-cents worth.
Bill
On Monday, January 5, 2004, at 11:53 PM, Gary Shelton wrote:
James Morgan wrote:
We need to get this 9600 cooling issue clarified so people don't burn their computers up.
The principle of computer cooling is that (1) air must be drawn in somewhere near the bottom of the case, (2) air must be blown over the parts that need cooling, and (3) heated air must be exhausted out somewhere near the top of the case because (A) Heated air wants to rise and the easiest and most efficient way to move it is up and (B) Crucial parts in a computer that run hot, ie hard drives, processor, PCI cards, must have air flow over them to carry away excess heat.
In the case of the 9600 the large (120mm) side door fan is placed down low on the side door and (in later models) a plastic shroud is used to assure that air drawn in does not go back out of the door vents (which are little round holes all the way along the bottom edge of the door) but goes upward into the upper box as it should . The fan itself is placed so as to blow the incoming air over the parts most in need of cooling. In a stock machine this is the PCI cards and the processor. And, if you add two hard drives to the black plastic drive mount plate, these two hard drives will be directly in front of the fan so that they also are cooled by the incoming air flow. If you look inside the 9600 case you will see that it was designed so that this incoming air flow would be directed to these areas that need cooling.
When upper box portion of the 9600 case is locked down there is space behind it to accommodate the motherboard and there are holes in it, both on the bottom and back, on the motherboard side, to allow air to move upward and into it. Yes, these slots and holes can get crowded with cables, and that is why I put a larger fan on the outside of the case, directly over the power supply fan, to increase the flow of air up into the upper box portion, draw more air out through the power supply, and exhaust heated air with more force out the back of the computer.
If you set up a 9600 with both fans blowing air out of the case you simply do not have the needed incoming air flow. Incoming air will have to seep in around the cracks in the front faceplates and the PCI slots, which are too small to allow the volume of air needed and do not direct the incoming air onto the crucial parts that need cooling.
The Avid system came with a new side door for the 9600 which has a more powerful 120mm fan in it and which blows incoming air directly over the PCI slots to cool the Avid PCI card.
If someone has a 9600 with the 120mm door fan mounted backwards so that it is exhausting air through the side door vents, that is certainly their privilege. And if it works for them, great. But I cannot emphasize enough that the 9600 was engineered and designed to draw air INTO the case through the side door vents, move it upwards into the upper box and exhaust it out the rear through the power supply. There are upgrade variations one can add to this principle, but the principle of drawing air in low and exhausting it high must guide any modifications for proper cooling.
More principles: It does little good to move heated air around inside a computer case. If you want to improve cooling you must bring air in from outside, move it over the parts that need cooling, and exhaust it somewhere. And cooling fans have to be cleaned periodically because they lose efficiency as dirt builds up on them. In the 9600 I take the power supply out and use high pressure air spray and Q-Tips to clean the fan and inside the power supply.
I have 8 highly upgraded 9600's and I have studied 9600 cooling issues extensively. I plan for at least some of my 9600's to be around for another twenty years, so that people who want to access my graphic archives can fire up a 9600 and print them out. I have made an extensive study of the inside of the 9600 case.
If you don't have the money to replace your stock fan, take your old 120mm side door fan out, clean it, and put it back in so that it draws air INTO the case. After you start up your computer, place a piece of paper over the side door intake vents. The intake airflow should be strong enough to suck the paper firmly against the door. If the old fan doesn't hold the paper tightly to the side of the case or if you have added devices to your 9600, buy a more powerful (6 Amp) 120mm fan and replace the stock fan. Be sure to plug it into one of the power supply connectors. The stock fans in existing 9600's are getting old now and newer, more powerful fans are readily available. Replace your stock fan before you burn up a hard drive, not after.
As I've already stated, I know nothing about the 9600 case. I was loathe to weigh in on this discussion, since I am inadequately armed for any sort of conflict. I did orient the fan so that it blows out of the case, rather than draw air in. In my case, it does in fact run cooler - my idle temps are around 48'C, and the CPU peaks at about 56'C. It drops down nicely after the load is removed as well. These are all positive improvements, and after several days of continuous use, it doesn't seem to fluctuate from the above-mentioned temperature range.
My 9600 isn't particularly loaded, though. I have a single 7200RPM ATA drive in the lowest 5.25" tray, an Apple 12x CD-ROM in the second bay (below the floppy), and an Apple G3/300 in a CarrierZIF card with the cheesy XLR8 heatsink. I have 5 of the six slots filled, but there aren't really any cards that generate a lot of heat - a USB/Firewire combo, a firewire card, an ATA card, an Intel EtherExpress Pro/100, and a Nexus 128. My case sits on the table, behind my monitor, so there's no carpet to interfere with air intake, etc. No doubt mileage may vary with regards to cooling in a setup different than mine.
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