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peltier

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Blueface

Registered
Joined
Feb 12, 2001
Hi, I just use 80 watt peltier on p3 700 slot 1with alpha p3125 and 300 watt power supply. The temp never get down to cold but it stay 30 c at idle. How long will it take the peltier to get cold? Is it instant cold or gradually cold? thanks
 

LimeyGreg

Senior Member
Joined
Dec 20, 2000
Location
Los Angeles
It should work straight away. What were your temps before installing the TEC and were you using the Alpha? If your HSF is not good enough you will get higher temps than you would without it as it now also has to dissipate the heat generated by the peltier as well as what is produced by the CPU.
 
OP
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Blueface

Registered
Joined
Feb 12, 2001
Thanks, the temp before is 34 c and using alpha heatsink. I disassembled the cpu and peltier and clean up the artic silver that I used on the peltier. It start to get cold but not very cold. Like Wild Andy said to get sub zero temp needs water cooling.
 

heavenly

Registered
Joined
Dec 25, 2000
Hi , The peltier should cool much more if it is correcly installed and gets the power it needs! I have had a simulair setup and the idle temp was 3 to 4 celsius, and full load was about the 20's celsius. what kind of fans do you have on the HS ? The best way to power a peltier is by giving it it's own powersupply!!
Good luck
 

LimeyGreg

Senior Member
Joined
Dec 20, 2000
Location
Los Angeles
Okay, try couple of things. Lapp your heatsink. Use a cold plate. If you can, clamp your cold plate directly to the heatsink, then use clip/bracket to mount to HSF/TEC/Coldplate to CPU.

For a TEC to work properly it needs several things. Sufficient power, sufficient cooling and sufficient mounting pressure. This latter item often gets overlooked but a TEC requires around 150~300 lbs/sq inch of clamping pressure, depending on it's specs. If you tried to achieve that against your cpu you'd have one dead puppy - hence the cold plate being directly clamped to the HSF with the TEC in between.

One other advantage of a cold plate is that it acts as a reservoir and prevents wild temperature fluctuations which can cause thermal shock and mechanical failure.
 
OP
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Blueface

Registered
Joined
Feb 12, 2001
I used delta fan on the heatsink, with al cold plate, right now idle at 10c and load at 26c, But when I benchmark with sandra the dhrystone only 873 mips and the whetstone only 336 mflops on p3 700 mhz. what might be the problems now ? I used kingmax 128 pc150, annihilator 2, cdr,cdrw, 1 hd and 1 scsi cheetah 15000 rpm with adaptec 29160. Is it not enough power to run the cpu? thanks again
 

stool

Senior Member
Joined
Dec 20, 2000
Location
Albany, NY
Its enough power for the CPU, but not enough for the pelt. It could be that you need to get a better grade PSU or add a second to power the pelt.
 

LimeyGreg

Senior Member
Joined
Dec 20, 2000
Location
Los Angeles
Pull your peltier and see what your cpu benches come to, if they are much improved then likley it's the psu. I'm running a P3-550E @ 850 Vcore 1.9 "original panaflow orb" HSF, no peltier and my cpu does 2313D/1148W so I'd say your scores are not too good.
 
OP
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Blueface

Registered
Joined
Feb 12, 2001
Hello again, I took the peltier a part and reassemble again, this time I did not screw it very tight and it is back to normal again. Last time, I screwed the cpu and backplate to hard(luckily did not kill the cpu) that's why the score is very low in sandra. Right now, the score is back to normal and the temp at idle around 15c. I'm happy with it now. It definitely need second psu but I'm done, tired already! Thank you guys!
 

jonk

New Member
Joined
Feb 15, 2001
>a TEC requires around 150~300 lbs/sq inch of clamping pressure, depending on it's specs. If you tried to achieve that against your cpu you'd have one dead puppy - hence the cold plate being directly clamped to the HSF with the TEC in between.
If I want to use 4 machine screws to sandwich my TEC in between my HSF and coldplate, how much torque do I put on the screws to get 150~300 lbs/sq inch of clamping pressure???

Thanx, Jon
 

jonk

New Member
Joined
Feb 15, 2001
Dunno, I haven't drilled and tapped the hedgehog yet. Maybe 3mm .50 pitch - I think that's what Alpha uses on their sinks.