View Full Version : Ducted Orb Cooling

9th January 2001, 06:51
Due to alot of SCSI stuff and all them other boards that generate heat, my inside case temp is 82-84F despite numerous fans. SO my Chrome Orb on the 900MHz T'bird had all it could do to reject heat.

The Arctic Silver helped alot, cutting a couple of degrees off but it would still reach 48-50C+ when overclocked to 1000MHz and running 3D Mark 2000. (Until I get a BIOS update past UL that allows me to boot from SCSI that has higher multipliers, I can't get much higher).

I resorted to ducting ambient room air into the center of the orb. Nothing new here, HP has been cooling its Vectra desktop CPU's like this for years. But it works great.

I call this "Ducted Orb Cooling."


I used 2" PVC pipe and elbows from central vacumn plumbing. This PVC is much thinner wall than regular plumbing PVC, easier to work with and not as bulky. The inside elbow is just about touching the fins of the orb.

I drilled a hole in side cover to mate with the duct. I wanted to go straight out, but the hole would have been in the middle of the case finger ridges, hard to cover nicely. I will order a grille or grille with filter to cover the hole.

At idle now, room temp at 72F, I am at 29MB/32CPU, (84/87F). Running 3D mark benchmarks at 1 GHz, temp is 30MB/46CPU. The temp will then drop a degree about every 20 seconds at rest. So check your inside case temps and if high, get creative with ducting. Will make any cooler more effective.

If I don't cover the hole, I have options to draw cooler air from the floor in front of the PC, instead of drawing on the warm air being exhausted out the rear.


And for really serious overclocking efforts in fall and winter......


ABIT KT7 non-RAID * 900MHz Athlon T'bird * 128MB Crucial 7E PC/133 RAM * Two Cheetah LVD's * Barracuda UW * DiamondMAX IDE * Plextor Ultraplex 40max/Plexwriter 12/4/32 * Hitachi IDE DVD * 2940U2W * SB Live * 3Com 905B-TX NIC * 3Com Courier V. Ext. * Hollywood + * Win 98SE, Win 2000 *

[This message has been edited by SCompRacer (edited 10 January 2001).]

9th January 2001, 08:10
Does any air actually go down that pipe in the last two photos?!?

BTW: Nice hoover! http://forums.murc.ws/ubb/wink.gif


"Life is what we make of it, yet most of us just fake"

9th January 2001, 08:40
Nice job!!!! I bet it really cools good this time of year with the tube out the window.


9th January 2001, 11:50
How about adding a venturi inlet?

Why didn't you just throw some of those SCSI devices into an external box? You don't even need to turn on the external box many times if you place devices correctly.

9th January 2001, 12:11
How about adding a venturi inlet?

If adding one to the intake it would reduce the airflow to such a degree that it would outweigh any benifits.

It can be done at the HS (best place) if the HS was designed for it. Since this is an Orb, that was already done.

9th January 2001, 12:36
Wouldn't you get adequate airflow by using an oversized venturi which narrowed down to 2"?

9th January 2001, 13:28
The cooling the Venturi effect gives, occurs only when a gas expands.

Sir Hitech
9th January 2001, 14:25
" Does any air actually go down that pipe in the last two photos?!? "

I can see what Steve is getting at. Warm/Hot air rises up and cool air sinks down. I think you would have enough better result tilting the pipes up.

9th January 2001, 15:22
Oops ... you're right Mike, I was thinking backwards.

I still think he should just move some of the SCSI devices out to an external box. I really enjoy this arrangement and it makes it easy to move peripherals to off-site PCs (work or friends).

9th January 2001, 16:15
Originally posted by xortam:

Why didn't you just throw some of those SCSI devices into an external box? You don't even need to turn on the external box many times if you place devices correctly.

Too much stuff laying around now, rather have it all self contained. The hottest drives are in the top of tower, only an IDE and a 7200 RPM UW SCSI in lower.

Just curious what internal temp a regular non-SCSI PC has is in lower case.

The pipe out the window was for humor, though the pipe to front of PC actually nets a small gain as the area behind/next to the PC is warm exhaust air. I usually close the heat duct when I am working in here a long time as the PC and monitor do add heat to room over a period of time.

[This message has been edited by SCompRacer (edited 09 January 2001).]

11th January 2001, 22:28
<font face="Verdana, Arial, Helvetica" size="2">The pipe out the window was for humor</font>

Just when you had my attention! Whaaaaaaaaaaa