View Full Version : What are average temps with a 72W peltier and P3 (air cooled)?
I've been out of the forums for a few weeks while I upgraded my motherboard's temp monitoring abilities (Abit BX6 r2 that required the cpu diode fix). I now have real thermal diode temps and they were very interesting.
I have a 72watt peltier and 3/8" copper coldplate all attached to a GlobalWin VOS32. I spent a great deal of time modifying my HSF to allow me to use screws for mounting to the cpu (much tighter to the CPU die). Anyway, the temps are now as follows:
Old (without peltier)
CPU Speed 868Mhz (highest stable possible)
Ambient temp 27C
CPU Idle Temp 35C
CPU Full Load 42C
New (with peltier)
CPU Speed 902Mhz (highest stable possible)
Ambient temp 28C
CPU Idle Temp 18C
CPU Full Load 26C
So there you have it. I figured I'd be getting much lower temps than this, but they still manage to be less than ambient at full load.
I am curious though-Should I follow the same rule for thermal paste on the peltier as I would for the CPU core? I always use a very thin layer of paste on the CPU and I did the same thing on the peltier coldplate surfaces. It occured to me that a thicker layer might be more beneficial, given the less that perfectly flat surface of the ceramic peltier plates. If anyone has any suggestions, I'd love to hear them.
Just an update, I did some testing today and have some new info to post.
I decided to experiment with lower settings, both frequency and voltage, to determine the lowest possible temps from the thermal diode. All you people who have P3/Peltier experience let me know if this looks right:
P3 @ 466Mhz (P3 700@ 66Mhz FSB)
Core @ 1.5 volts (!)
My ambient temps didn't change at all but my idle temps dropped to 1C. At first glance this sounds great but according to my best guestimate, the total wattage of the CPU should be around 14watts for these settings. Correct me if I'm wrong, but shouldn't a 72watt peltier get better results than this?
Bear in mind that I have everything clamped down tight, with excellent insulation on the front and back of my SECC2 cartridge. As always, any suggestions are greatly appreciated.
-=UR=- Ranger
10-02-01, 02:59 PM
You could lap the VOS 32, Iīm using one on my slot A Athlon an the base was not very smooth..I could easily feel machine Marks on it. I got a 6 degrees temp drop after lapping..you should try this also if you havenīt yet.
Forgot to mention that I'd already done that. I lapped the cold plate as well. And the CPU core is lapped too. I'm not sure the last one accomplished much. Maybe a 1C drop.
.. AE 86 ..
10-04-01, 11:12 AM
!And the CPU core is lapped too
how do u lap the core of a cpu
Very carefully!
Seriously, I don't know that I'd recommend it but here's how I did mine:
I wrapped the cpu in electrical tape to avoid the possibility of getting dust on the parts and lightly sanded the core with 600 wet sandpaper on a pane of glass. I sanded the core till the blue finish was gone.
I'll add that I wouldn't have done this had it not been for pattern of thermal grease the I kept seeing on the core. It was obvious that the core was not contacting the heatsing over about 25% of the surface. I say not contacting, but what I mean is not as tightly as the other 75%. After the procedure it appeared to be a better contact. Again, I only saw temp decreases of about 1 degree celsius, so the value of this is debatable. Hope that helps!
Here a bump, there a bump...
JetMech
10-06-01, 08:35 PM
You haven't mentioned condensation. Seen any?
Glad you asked! Actually I took extra care to make sure everything was well insulated and I haven't seen any evidence of condensation.
I do believe I've figured out the problem with my setup though. And also the remedy!
There seems to be an issue with the way I clamped the peltier and coldplate to my heatsink. I read a few reviews that recommended the use of super glue. I have to say that I don't think this is a good idea with the use of a peltier. Mostly because of the amount of time it takes to position the elements. By the time they're set, the glue has hardened. That seems to be the case with my setup-the glue hardened and the surfaces of the parts where not tight enough to allow for a good heat transfer.
The way the setup is running now is showing a marked improvement. My idle temps are now at 9C!
Thanks for the posts and feel free to add questions or comments.
JetMech
10-07-01, 01:23 PM
Is the sys in your sig the one you have the pelt on? My interest in all this is because I thinking about putting a pelt under my swiftech. Something like a 85 watt.
I've tried to post this 3 times now! There must be some issue with the server or something. Every time I try to post, I get a page not found error. So here goes nothing.
The sig is my current system with the peltier. I would recommend going with similar setup with one word of caution. If you are trying to go air cooled on a socket 370 rig, I would worry about the heatsink's physical ability to dissipate that much heat.
The only reason mine works as well as it does, (which isn't all that great) in my opinion at least, is the sheer size of this heatsink. I'm getting about 45 degrees C on the fins of my sink, which would suggest it's close to saturation (it may have a few more watts it could deal with but that seems a bit hot for the fins). I'm not sure you'd get that with a smaller socket sink. The fact that yours is Swiftech might help though. I'd probably still go with a 72 watt just to be on the safe side. Your call though. I'd be interested to see your results if you went with the larger one. Let me know if you need any more resources or suggestions.
Sorry there where so many posts on that. It was one large post but it wouldn't allow me to update until I cut it up into smaller chunks. Hope it all makes sense.
Thats one way to boost your posts score :D
Do you think you can post some pics of this beast?
JetMech
10-09-01, 06:46 AM
Originally posted by Muggy
Sorry there where so many posts on that. It was one large post but it wouldn't allow me to update until I cut it up into smaller chunks. Hope it all makes sense. Thhanks for the info Muggy. Got the HSF yesterday and after installation can't get a picture on monitor. Can see drives posting, no beep warning. Working 12hr. shifts till thursday so it'll be a while before I can get the numbers I need to compute pelt size. I have some info that I printed from http//www.heatsink-guide/applying-peltiers/ and using it I intend to attempt a reasonable choice. I may not need it. I'll keep you posted.
Hi Muggy,
Your info is very interesting, I am thinking of adding a peltier to my cC0 700 too. The Leufken 72W kit for the Alpha 3125 looks pretty easy to install, only worry is that I will screw up and there will be condensation.
I am currently running at 157fsb and I want to reach 160+, my PCI cards and ram checked out well at 172fsb on my AMD system, so I know the CPU (or maybe the BE6II2.0) is holding me back.
Only thing holding me back from getting a peltier is that after going thru the trouble of installing the peltier, I may still be stuck at 157fsb.
Oh a question for u, are your modifications to the VOS32 permanent? Can u convert it back to the non-peltier stage easily?
Thanks.
Originally posted by JetMech
Thhanks for the info Muggy. Got the HSF yesterday and after installation can't get a picture on monitor. Can see drives posting, no beep warning. Working 12hr. shifts till thursday so it'll be a while before I can get the numbers I need to compute pelt size. I have some info that I printed from http//www.heatsink-guide/applying-peltiers/ and using it I intend to attempt a reasonable choice. I may not need it. I'll keep you posted.
That sounds familiar. I'm still not clear about whether this is a slot or socket CPU. If it's slot, then it sounds suspiciously like the CPU isn't fully seated. I've had this happen twice and the first time it was poorly seated. The second time I could find no real reason. I powered down the system and disconnected the PSU lines from the mobo. Once it was all back together, it seemed to work. I may need to invest in a new power supply at some point. Especially since my current setup requires a second AT supply which has no where to go but next to my case. Not the prettiest but it works well enough.
So JetMech, does your name mean what it says? If so, I'd imagine you have some great stories to tell!
Originally posted by QSW
Hi Muggy,
Your info is very interesting, I am thinking of adding a peltier to my cC0 700 too. The Leufken 72W kit for the Alpha 3125 looks pretty easy to install, only worry is that I will screw up and there will be condensation.
That kit would probably be the best investment in the long run. I just didn't want to run out and purchase a new HSF when I was pleased with the one I had. In hindsight, I should have gotten the Alpha. Not that the VOS32 is a bad HSF, it just isn't widely supported by peltier kit retailers.
As for condensation, I wrapped a strip of common closed cell weather stripping around the peltier/coldplate before installing the white foam that comes with most kits. This approach ensures the peltier/coldplate doesn't touch the air. The rest of the CPU is insulated using the kit's contents and weather stripping in spots the kit's foam misses.
My kit came from Peltec, but I'd have to recommend going somewhere else unless you have a bit of patience. Delivery time wasn't an issue, but finding the appropriate info on how to get all this going took a coupla weeks.
Oh, and my CPU is cB0 so I would think your results would be impressive (they're already way ahead of mine!).
Originally posted by QSW
[BI am currently running at 157fsb and I want to reach 160+, my PCI cards and ram checked out well at 172fsb on my AMD system, so I know the CPU (or maybe the BE6II2.0) is holding me back.
Only thing holding me back from getting a peltier is that after going thru the trouble of installing the peltier, I may still be stuck at 157fsb.
Oh a question for u, are your modifications to the VOS32 permanent? Can u convert it back to the non-peltier stage easily?
Thanks. [/B]
Yes, the VOS32 is completely returnable to the factory state. I only replaced the screw in clips that attach to the heatsink. They use pins that run through the CPU and are secured using a spring clip. I think this method is terrible even without a peltier so I'd recommend replacing the clips with screws if you go for this HSF. I made new 'clips' out of Lucite plastic and drilled holes to allow the use of bolts. It sounds more complex than it is. You'd have to know the design of the VOS32 to really get the idea. Suffice it to say, it works better than using clips and I can always go back if need be.
Originally posted by YMAN
Thats one way to boost your posts score :D
Do you think you can post some pics of this beast?
I'd love to, except that I don't posses the elusive 'digital camera.' There's really not much to see though. The system looks like a typical PIII with GW VOS32 bolted on the side. There is a bit of white foam sticking out of it and the peltier leads, but that's pretty much it. I even left the PIII case on the CPU. All in all, it looks pretty much stock.
Thanks Anyways.
Is the peltier plugged in the main power supply,
or do you have 2?.........How ya gettin the power?
What is your Power Supply?
Originally posted by YMAN
Thanks Anyways.
Is the peltier plugged in the main power supply,
or do you have 2?.........How ya gettin the power?
What is your Power Supply?
I've got 2 PSU's. One AT for the peltier and an ATX for everything else. I've got the AT wired up with a relay to turn on when the ATX supply is powered. Seems to work well, though I don't get a true 12 volts with the AT without a load on the 5 volt rail, it's more like 10.5 volts. It doesn't seem to affect peltier performance though. I tested it with a bench supply and the efficiency was abou the same from 11-15volts. So I do sacrifice a small amount of performance but not more than a degree or so.
I'll post PSU brands when I get home. I'm fairly certain I have a no frills Enermax for my ATX supply. Rated at 250watts. The AT is an old PSU out of a 486SX 25 machine. It is rated at 8 amps constant for the 12 volt line though.
Muggy: I just visited Peltec's site, I am interested in their 86 watt kit for the 3125. I wonder if it will make a big difference over the 72W kit. I e-mailed them some questions but the mail got bounced back to me.
Anyway, I wanted to ask you what kind of silicone sealant do u use? I am worried that the regular kind at the hardware store may not be able to withstand the heat coming from the peltier.
Originally posted by QSW
Muggy: I just visited Peltec's site, I am interested in their 86 watt kit for the 3125. I wonder if it will make a big difference over the 72W kit. I e-mailed them some questions but the mail got bounced back to me.
Anyway, I wanted to ask you what kind of silicone sealant do u use? I am worried that the regular kind at the hardware store may not be able to withstand the heat coming from the peltier.
You'll need to use the info@peltec.com address. The sales@peltec.com doesn't seem to work anymore. Let me know how you go!
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