GOAL - Air cooling with no fans (edit: GOAL reached)

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Mats
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Joined: Fri Dec 26, 2003 6:54 am
Location: Sweden

Post by Mats » Fri Aug 20, 2010 12:54 pm

maalitehdas wrote: CPU Core2 duo E8400
clock 3,0GHz -> 1,8GHz
voltage 1,25V -> 0,8V
wattage (idle/load) 36W/65W -> 12W/17W
Is that the TDP? I have to tell you that it has nothing to do with the real world usage.
It tops out at 40 W, in worst case situations. I've never seen a review showing more than that. TDP is a limit, you should read it as <65 W.

Here's a classic movie about oil cooling, it makes it look so easy and fun!
http://www.youtube.com/watch?v=PtufuXLvOok
http://www.pugetsystems.com/submerged.php

maalitehdas
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Location: Finland

Post by maalitehdas » Fri Aug 20, 2010 10:31 pm

That's the TDP and surely never reached in normal use, I think that normal use add only 1-3W to idle consumption. Maybe you can reach the TDP with 100% burning thou? After undervolting I'm getting that 17W with 100% burning, but I have not used the meter with normal voltage so I couldn't tell at the moment.
[size=75]E8400 @ 1,8GHz, passive cooling | CPU Queen 7163 points | CPU stress test two hours, temperature 43C | fan rpm's [b]ZERO[/b][/size]

mkk
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Post by mkk » Sat Aug 21, 2010 2:47 am

How about adding a slow fan to the chimney? :) (top or middle)
Wider chimney perhaps? If you can find another spare tube. Could make for an interesting comparison.

Mats
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Joined: Fri Dec 26, 2003 6:54 am
Location: Sweden

Post by Mats » Sat Aug 21, 2010 4:16 am

maalitehdas wrote:Maybe you can reach the TDP with 100% burning thou
In fact, you can't. Here are xbitlabs results, using Prime95:
Image

maalitehdas
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Joined: Tue May 27, 2008 12:04 am
Location: Finland

Post by maalitehdas » Sun Aug 22, 2010 3:46 pm

mkk wrote:How about adding a slow fan to the chimney? :) (top or middle)
Wider chimney perhaps? If you can find another spare tube. Could make for an interesting comparison.
Thanks for ideas, but...
- If a fan would move the air, chimney would have no use. It's either chimney or fan, and in my case I wanted to get rid of the fans.
- If i used wider chimney, i'd need to cut the case too. There is a 12cm vent on top of the case, so I suppose 12cm tube is ideal in P182. More height would surely add to the cooling performance but in my room it's at max too.

Mats: Thanks for the link and info. I suppose my E8400 would use at max 29W with original clock and voltage then, and hitting the TDP (if even possible) would need serious overclocking+overvolting. The low idle readings were a suprise too, I suppose my undervolted CPU is <2W at idle then. I should edit one of my earlier posts by these facts but i'll pass...
[size=75]E8400 @ 1,8GHz, passive cooling | CPU Queen 7163 points | CPU stress test two hours, temperature 43C | fan rpm's [b]ZERO[/b][/size]

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