FYI: CPU temp down to (minus) -11C on a P4 1.8

Matt Simis

Tis quite sweet indeed. I just thought Id try out a P4 as my main system (had AMDs for 2.5 years now).

Spec:
P4 1.8A NW
Abit BD7 845D Motherboard
156W Peltier
Overclockershideout.com Z4 Waterblock
A big Aquarium pump I got in Petstop
A Mini Freezer I got in Power City.

Yes, I know using a Freezer is silly and crazy etc..
But its small and you wouldnt even notice it under the desk.

The -11C was running Win2K and not doing anything, just clicking around. Under load it increased to 0C.

Ive just rebuilt this system, so no overclocking yet. I had to rebuild as my first P4 motherboard died (Asus P4S333 SiS645 chipset), it couldnt handle the pressure of the waterblock (and clamps), seems to have pushed the Socket down (not visibly). Mind you, Ive read alot about the P4 sockets being very weak, so Im not surprised.

Ill post pics\info if anyone is interested later..




Matt

elexes

very nice ya mad git

yellum

Post pics, post pics !

Lucutus

Excellent, give us all a look!

What do you have the 1.8 running @ ?

Luc

BioHazRd

Forgive me if this sounds stupid, but do you have any condensation problems while running at temperatures lower than the surrounding ambient. If not I'm well impressed:D

Matt Simis

Clever fellow! Condensation is a problem alright, but less than people think.

I took these steps to get around it:

I put it all in a Desktop case, which eliminates water dripping on components "below" the cpu (ie GFX).

I also used "Conformant" Spray to "seal" the motherboard. It kinda is like liquid plastic, hardens and is virtually invisible.

Finally, the waterblock and tubing has foam lagging all over it, reducing its contact with the air, therefore limiting condensation.


It will be in the pictures!



Matt

Gavin

How come you have the peltier and the watercooling ?
What sort of temp would the peltier on it's own get it down to ?

Gav

Matt Simis

Ah Verb, Peltier newbie eh?


A Peltier draws in Heat one (the cold side) side, then outputs 3x the heat the otherside (hotside) . Melting a normal Fan Heatsink is a possibility!

If you use a Peltier on [standard] water cooling, you most likely wouldnt be able to cool the water quick enough to get the benefit of the Peltier. When the Peltier isnt being cooled enough, the heat spreads thru the device bank onto the "Cold Side", onto the CPU. It does however depend on how good the water cooling is and how much heat the CPU outputs.


The Water Block on its own (with the chilled water from the Freezer) can get the CPU down to (under load) +10C, with the Peltier its around the 0C mark.




Matt

Gavin

heheh yeah thought about it for a minute and figured that was why

And have you thought of using freon as your cooling liquid ?
Easily available I am constantly told by an engineering friend. How much did the water cooling cost and how loud is it ? What sort of temp will it get down to without a small freezer ? :rolleyes:


Gav

BabyEater

I was wondering how much you paid for the freezer and pump.
As i was thinking of something similar without the pelter and using a fridge instead of a freezer as i feared condensation.
I seen a pump for €60 but i was looking something cheaper.
I'm making me own waterblock so i have no worries there .
Now hurry up and post some pics.

Matt Simis

@Verb

Engineer types are always recommending Freon for some reason, but my research [geek mode on] found it less useful than I first thought:

http://hypertextbook.com/physics/thermal/heat-sensible/index.shtml

On this website we can see that the Specific Heat capacity (SHC) of Freon is 600 cp (J/kg·K), while Water: (liquid, 0 °C) 4217.6 cp (J/kg·K). If I understand any of that :rolleyes: , that means that water is several times better at extracting heat.

However, since Im using a Freezer, I needed to put a lot of Antifreeze in it to prevent the water freezing, so my liquid is more like "Alcohol, methyl 2530 ", so not quite as good as straight water.

Another disadvantage of Freon is that at all temperatures I could attain (-20 tops inside the Freezer) it turns to Vapor.

If anyone knows of a liquid that has a low freezing point and good SHC, let me know!

Without the Freezer or Pelt, my Water Cooling (with a decent Radiator) was about 2 degrees over Ambient (at load).. 30C tops.



Matt

Matt Simis

@BabyEater

The pump cost about €55 (its a good one) in Petstop. The Freezer cost €100. To all you people with better things to do please refrain from posting "what a waste of money" replys!

I like messing around and I reuse\pass on everything...




Matt

Inspector Gadget

...I'm pretty sure that Freon is a gas at room temperature - i think it boils at subzero temperatures - and it's a greenhouse gas, to boot, so I'd say that would make for two black marks against it unless (or perhaps even if) you have a sealed, high-pressure cooling system?

Gadget

Gerry

Well hopefully you should be able to get some crazy speeds out of the machine, I know lucutus's 1.6 is at 2.4 already with just the standard cooler. These northwoods are getting very tempting....

elexes

so anysigns of the pic

The_Conductor

Ok- so you have your P4 1.8GHz running at frigid temperatures, presumably so you can blast the clock speed upwards. Given the multiplier lock- how high can you manipulate the core speed by playing with the FSB, and what effect does this have on temperature? BTW- Athlons always are a hell of a lot hotter than P4s- mainly because the P4s' are cut from .13 micron silicon wafers, and the Athlons (K7s) are cut from .18 micron wafers. If you clocked it- the P4 also uses a lot less power at a comparable clock speed than the K7 chipset. Will be interesting when AMD bring out their new chips this autumn, the Athlons are at the end of the road in any case from a scaleability view point.
How high will the Abit board let you bring the processor up to?

Post a pictures- should be interesting.
If anyone is interested- www.overclockers.de have a lovely little video clip of playing Quake 2 on a P4 and an Athlon system and removing the heatsink in mid sequence. I'll not give the story away.

Gerry

Well, the board should be good for at least 150mhz fsb, perhaps 170 - 180 with serious tweaking. The limit of the cpu will be hit first, 150fsb = 2.7ghz. The abit i845d based board will let you keep the pci bus at relatively normal speeds, so you only really have to worry about the ram.

I think when amd transition to a 0.13 micron process for the palomino core ( it will be called thoroughbred ), there will not be nearly the same drop in power dissipation as there was when the p4 went from 0.18 to 0.13. AMD have been using elements of 0.13 technology in their 0.18 process since the tbird, and the palomino to a greater degree. So it will not be such a big jump.

As far as temperature increase goes, it will be quite linear until matt increases the core voltage. If the watercooling system can't keep up there will be a major spike in temperature.

Matt Simis

Sorry about the delay in Pics, had internet connection problems at home. I was going to upload them in work today, but I forgot the cable for my digital camera (yes, Im an idiot).

In regards to overclocking, not good unfortunately. Shortly after I purchased the 1.8a, I read that all the recent batch were rather bad at overclocking. The highest I can get this one to is 2500, and its not 100% at that either. Considering heat is not an issue, and the board it quite good, it only leaves the CPU.
I modded the CPU to have a default Core voltage of 1.7v (instead of 1.5) and that allowed me to specify upto 2.2 in the BIOS of the motherboard. Whats weird is that the system wont boot if I try to set the bios to higher than 1.85v. Very annoying..
I hear the 1.6A are faring better (in overclocking), anyone out there wanna swap their 1.6 for the 1.8??

Gerry, in regards to your last post, you are absolutely right. After about 2hours (at 2400mhz) the freezer can no longer keep up with the heat from the Peltier. I had a similar problem with Athlons, but thought that the .13m on the P4s would be cool enough for the Peltier\Freezer. The water reaches +7C in the freezer eventually, although with the athlon & Peltier it reached +38C (which IMO is crazy). It looks like Peltiers have had there day, since CPUs are increasing in heat steadily, I cant see a use for them anymore.

At least the Freezer is relible and efficient, it alone will keep the max CPU temp to around 12C, idle about 5C..

Ill post the pics anyway, perhaps there are improvements to be made in the setup?



Matt



PS: At 2400 (170mhz RAM speed), it gave me my highest 3Dmark 2001, 9700 (about 500 higher than my 1910mhz AthlonXP). This was on a Radeon 8500 with no tweaking or overclocking of the video card in WinXP.

The_Conductor

Heres a tech site with a rake of detail, both temperature/noise/price/scaleabilty/stability related. Its more aimed at the XP than the P4- but might give you a few ideas.

Cheers,

Shane

http://www.ocinside.de/cgi-bin/coolertest/coolertest_e.cgi