Cooling the 6400

This page has all the info I have collected on cooling the 6400
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Charles sent me some info on his cooling method of a Sonnet G3 in his 6400. He sent me 2 letters and some pictures of the fan installed. NOTE that the first letter below has temp readings in F and the second letter is in C so please do not get them confused :) Thanks Charles


I just wanted to tell you about a way for users with G3/L2 Upgrade cards to cool down there CPU temperature. I have a fully populated 6400 upgraded with a Sonnet G3/L2 400 MHz, a Monster 3D II card and a ATI Xclaim 3D Plus. I've noticed some slowdowns, lockups and other anomalies after the system has been on for several hours. I figured it maybe an overheating issue so I decided to see just how hot this puppy gets after several hours use. Being that the weather is changing and my computer room can get a little hotter than usual, my average CPU temperature using Gauge Pro and also Sonnet's Metronome was about 116F to 120F degrees. Not knowing what is an acceptable temperature I thought about how I can cool down the CPU. I remember I had a spare Voodoo I/II cooling fan which let me do insane overclocking. It is a simple device that basically is a 486 CPU fan attached to a very bendable piece of metal which is mounted by sharing the same screw as the PCI card of which you are trying to cool down. I figured let me give it a try so I opened up the 6400 and figured out a way to get this to work. Since I am not using the top bay for anything, I snaked down the spare powerlead down to the logic board area so I can plug in the fan. I positioned the fan by very easily bending the metal which the fan is attached to between my Voodoo card and the Sonnet Upgrade, but more pointing towards the Sonnet Upgrade. (I also realize that I should put the Voodoo Card furthest away from the Sonnet being that it does generate most of the heat) My results were incredible! For a good hour and a half I made sure I played as many Voodoo games as possible to get the fire burning. I then took a temperature reading and it was only 104F degrees!! That's 116F down to 104F degrees... I'd say that is significant! This cooler can be purchased online at for $16.00 plus $2.50 shipping. I hope this can help others with similar problems. I recommend it even if you don't have any problems with your G3 Upgrade. Cooler is better!!!!!

Later he sent this more technical letter :)

More cooling info from Tiong: Tiong send his experience with cooling and will hopefully have some pictures soon :) Thanks Tiong.

Tiongs cooling fan image

7/22/2000 Extreme cooling of the 6400!: I got this letter from Richard who has a floor standing air-conditioned aimed at his 6400 with the covers off. He has gotten down to 7C degrees according to GuagePro! Wow, that's cold. I wonder what the room temp is in his place :) Thanks for the info Richard.

Richards Mac setup image

Richards GuagePro image

Could Gauge Pro be reading incorrectly? But he does have a 3" to 4" fan blowing out the side of the case and with the covers removed and the airconditioner aimed at it, who knows? Would have been nice to have this thing when I was experimenting with clocking my stock 603e CPU :)

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This page last updated 7/29/2000