Waterblock as a heatsink?

Can you explain this?

I've got a maze 3, asus a7v-333, 1/2" ID setup on a viaqua pump with a noname heater core externally mounted with 3 120mms.

I booted my computer and forgot to turn on the pump and the radiator fans. I didnt check my temps and went about computing.

My case fans were on but no other cooling. An hour and a half later I went to shut down and checked my temps. They were 69*C This was after an hour and a half of light computing on an athlon xp, (which to my knowledge Doesn't throttle at high temps.) Now I have decent case cooling but still 69*C after an hour and a half with no active cooling on the chip itself? MAYBE due to heat rising a very slow circulation was created naturally (the radiator was warm it never gets warm when fans are on). Oh and I am absolutely sure the pump was off as the surge pro it is wired to was off. All I can say is thank goodness I was at stock when this happened.

Can anyone with better knowledge of the subject confirm or deny my suspicions as to the cpu performing its own pumping by heating the water? Or perhaps explain this some other way?

Temps are ondie by the way.

Im sure it was by convection, does it have a copper top? then maybe it dissipated some heat by that, but Im sure it was a lot of convection, maybe if you get a temp probe to check water temp, you could be more sure...

you know i was playing counter strike for like 2 hours one day and my screen went funny and i started laggin then i shut down. so im like wtf happened. i lean down to make sure nothing strayed into my open case and guess what pump = not plugged in. the water block is the highest thing in my system. not i have the DB-2 by neo moses. alu top copper base.well it must have helped a little then i felt my tubing warm and as easily bendable as string i hurried up to plug in the pump and it slowly got firmer i think it was about to bubble or burst but wow. i thank the o/c gods everyday for these little miracles that we have happen to us every now and then. but i then realized that i have paid my dues to the same gods so as soon as i booted with normal temps i flipped off those o/c gods and said haha we humans are gonna have u beat soon...

Was your computer doing anything particularly processor intensive? Such as Folding or 3D modeling? If not, surviving only on convection could be possible.

It's a funny thing that I signed on just now to see this message, as I type my temps are going back down (34c now)

I got home from work about 10 minutes ago to find my wife sitting at her computer playing on pogo.com
Not thinking twice about it, I turn on my monitor and imediately turn to her and say "WTF!!!!" then lean over and plug in my pump.
What I saw when I looked at temps:
Mobo : 34c
CPU : 43c

she had apparently turned my computer on, then hers, connected to the internet (dial-up gateway) and proceded to play her games without even looking at my computer (she had even turned my monitor off)

luckily my water-block is the lowest point in my system, hence the still low temp of 43c after about 3 and 1/2 hours at idle speeds. of course I have no doubt that the temps would've skyrocketed if I hadn't happened to look at my temps and just loaded up NeverWinter Nights and started to play.

well Khan that sure is a good thing. you sound like the person that should relaytheir pump into their psu. this would help a lot. maybe even save u. what if u just left...but wow. good luck..

well boys, sorry but i dont believe these qualify as miracles. miracles are referenced as events or occurences that take place in defiance of the natural laws of the universe, as in a house lifting off the ground with no outside force acting upon it... talked about this bs in philosophy last semester - hey, i pay for this education, i gotta disperse this useless liberal arts knowledge somewhere. you are on the right track, the wb definetly acted as a heatsink, however we all know a passive heatsink couldnt keep those chips cool for long, but with the help of the case cooling they had to have helped. anyways, my explanation for the survival of the chips would be, in addition to the definite factor of the wb acting as a passive heatsink, a certain extraordinary property of water - Heat Capacity. the heat capacity of water is immense in respect to other substances (heat capacity of water 4216 J/kg*°C, pure copper 385 J/kg*°C), and i would think that the slowness with which the water increases in temperature had to play a huge part in keeping your precious little chippies alive.

ref: http://www.apo.nmsu.edu/Telescopes/...6_ConversionFactors/19950926_MProperties.html

Yes you are right with the first post convection did happen, but it was the second part of what happened. First you had conduction, the heat transferred from the CPU to the water block. Next you had convection, the heat from the water block heated the water, but the water was carrying the heat away from the water block. The heat generated from the CPU would have to have been great enough to heat all of the water to a point that the CPU could no longer function. Depending on the amount of water that was in the system would determine how long it would have taking the CPU to over heat. With the case fan(s) running it added in the removal of heat thru the hoses and from the water block itself.

of course this all just a guess.......

Just websurfing. maybe 1-4% average cpu usage. Thanks for the inputs.