Water Cooling Tweaking Advice Needed Please

I've been meaning to ask this question for a while, but just never got around to it, but now I've just got an Opteron 170 I thought I'd chase it through.

I've got an Asetek water cooling setup, nothing too fancy - standard CPU block, GPU block, single radiator mounted outside the case and a 12cm fan pushing air through the radiator and a 12cm fan at the front of the case pulling air in.

Now my temperatures aren't high by normal standards, but they seem high for a water cooled system (idle 28c-30c and under load up to 48c-50c). When the system is at full load it stays at 48c-50c and as soon as the CPU is idle again they instantly (within 1 or 2 seconds) return to 28c-30c. Even adjusting the speed of the fans seems to make no difference to these temps, even to a point where I can turn the fans off!!!

Is this indicative of something? I realise that I'm running a fairly low-end water cooling setup but it seems that it is doing it's job but it still surprises me that the load temps get so high.

If I wanted to get the load temps down, where should I be looking? A more powerful pump, a better radiator or a different CPU block?

Im not much of a fan of the Asetek kit but first thing i would do would be to get a dual 120mm radiator. Im not sure how much of a difference it would make, but thats the first thing i would do.....

NoodleHead said:

Im not much of a fan of the Asetek kit but first thing i would do would be to get a dual 120mm radiator. Im not sure how much of a difference it would make, but thats the first thing i would do.....

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I'm not sure I've got any additional room to install a dual rad, was thinking more along the lines of swapping components out for alternative makes:

Pump
Rad
CPU block
GPU block

I think one of my problems in doing this is I'm running with the 10mm tubing.

space--coyote said:

I've been meaning to ask this question for a while, but just never got around to it, but now I've just got an Opteron 170 I thought I'd chase it through.

I've got an Asetek water cooling setup, nothing too fancy - standard CPU block, GPU block, single radiator mounted outside the case and a 12cm fan pushing air through the radiator and a 12cm fan at the front of the case pulling air in.

Now my temperatures aren't high by normal standards, but they seem high for a water cooled system (idle 28c-30c and under load up to 48c-50c). When the system is at full load it stays at 48c-50c and as soon as the CPU is idle again they instantly (within 1 or 2 seconds) return to 28c-30c. Even adjusting the speed of the fans seems to make no difference to these temps, even to a point where I can turn the fans off!!!

Is this indicative of something? I realise that I'm running a fairly low-end water cooling setup but it seems that it is doing it's job but it still surprises me that the load temps get so high.

If I wanted to get the load temps down, where should I be looking? A more powerful pump, a better radiator or a different CPU block?

Click to expand...

Something might be wrong with the temp sensor.

IMO, if you can do all three.

bartsimsonii, grats on being the first person to make it on my ignore list. 58 useless and asinine posts in 4 days. grats.

space--coyote, if you want lower temps the cheapest thing for you to do right now would be to get either another 120mm rad or replace your current one with a Dual 120mm fan capable one. Replacing your blocks would also be a good idea, since they are acrylic topped, but you'll see the greatest results by increasing the cooling capacity of your radiators. Try that first before you do anything else.

First thing I would do is triple check your waterblock mount. Reseat it, check the temps, and repeat this process 2 or 3 more times, and see what temp you get each time. That will give you an idea of how well you're mounting it. When you feel like you have a better number (with some consistency) then we can go from there.

Maviryk said:

bartsimsonii, grats on being the first person to make it on my ignore list. 58 useless and asinine posts in 4 days. grats.

space--coyote, if you want lower temps the cheapest thing for you to do right now would be to get either another 120mm rad or replace your current one with a Dual 120mm fan capable one. Replacing your blocks would also be a good idea, since they are acrylic topped, but you'll see the greatest results by increasing the cooling capacity of your radiators. Try that first before you do anything else.

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Ouch mav thats pretty mean.

citronym said:

First thing I would do is triple check your waterblock mount. Reseat it, check the temps, and repeat this process 2 or 3 more times, and see what temp you get each time. That will give you an idea of how well you're mounting it. When you feel like you have a better number (with some consistency) then we can go from there.

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I agree...It's the mount for sure.

I think his mount and temps are fine... 30C idle 50C load... sounds like low end watercooling/high end air cooling to me. But then again I'm used to Prescotts, I get 29C idle and 43C load with an ambient of 20C. YMMV.

Maviryk said:

I think his mount and temps are fine... 30C idle 50C load... sounds like low end watercooling/high end air cooling to me. But then again I'm used to Prescotts, I get 29C idle and 43C load with an ambient of 20C. YMMV.

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It's not the temps, which are on the high side, but the fact that the chip cools rapidly. It has to get hot so there is a big temp differential between the CPU and block before cooling gets effective. I'll bet it also heats up fast too!

Some interesting thoughts here.

billb - you're right the chip does get hot quickly and does cool quickly. When I first got the CPU block I spent 3 nights lapping it to a very smooth mirror finish, and each time I replace the CPU I clean the block with surgical spirit (similar to rubbing alcohol), tint it with AS5, put a rice grain worth of AS5 on the middle of the heatspreader and re-mount the block, screwing it down with a half turn per mount of which there are two) until it is tight onto the CPU.

If I remove the CPU block, the AS5 is spread across the heatspreader as expected and I'm pretty sure it is making a good contact - so I'm not sure what else I can try.

From the sounds of it I might try replacing the CPU block first - any suggestions for a 10mm CPU block I could try?

Is this indicative of something? I realise that I'm running a fairly low-end water cooling setup but it seems that it is doing it's job but it still surprises me that the load temps get so high.

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2 comments
1 you get what you pay for ( weather that be in time doing research and peicing it together your self or buying a cheep kit all the way up to spending hundreds of hours building customs with the best parts)

2 while those temps are not great the behavior you indicated is typical and well within the cpu tolerance so there is nothing to worry about and if you are happy with the noise and the OC then there is absolutely no problem and no reason to change.

if you want to OC higher though you will want a system capable of removing more heat and that means at the least changing parts out and at most completely rebuilding a new system ( cooling)

space--coyote said:

If I remove the CPU block, the AS5 is spread across the heatspreader as expected and I'm pretty sure it is making a good contact - so I'm not sure what else I can try.

From the sounds of it I might try replacing the CPU block first - any suggestions for a 10mm CPU block I could try?

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thorilan is correct, better parts = better cooling. Why do you want to limit yourself to 10mm blocks? The cross sectional area (hence flow potential) of 1/2" tubing is 62% greater than 10mm.

As for choosing which CPU block to install, that's up to you. I like the Storm.
Did you check your lapping by reflecting graph paper off your block, or by looking for light under a straight edge? And you did use as powerfull as you can get magnification to check for scratches and "swirl marks"? How about lapping the CPU also (I can tell you for a fact that it voids your warranty though). I'm pretty good with my hands and have good magnification and I can't do as good as a machine shop. I've done it both ways, and a machine shop does a better job. I pay about $50 for a setup and $2-5 per piece for lapping. I see about a 3 F diferance between what I can do and what a machine shop can do. With a machine shop lap you can't spread the TIM (I use Shin-Etsu X23-7783D, 33% better thermal conductivity than G751) thin enough.

As for your AS5 application, skip the gob in the middle. Just heat up the block and the TIM, wrap some Syran Wrap around your finger and spread a coating as thin as you can. The gob is to take up the space between uneven surfaces. If you have a good lap, these are minimal and the only thing the AS5 does is fill in the microscopic (barely visible to the naked eye!) scratches left after lapping.

First thing I would do is triple check your waterblock mount. Reseat it, check the temps, and repeat this process 2 or 3 more times, and see what temp you get each time. That will give you an idea of how well you're mounting it. When you feel like you have a better number (with some consistency) then we can go from there.

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That's my suggestion as well. Going from load->idle you can expect to see a fair amount of drop, as the CPU is putting out a lot less heat. If you see a quick temperature change going from idle->load, then I would check your mount. Generally watercooling systems keep the idle->load transition relatively smooth.

billb - thank you for the explanations, I suspect that my lapping job could be better - perhaps I will have a word with the local machining factory, although I feel it may be wasted on the block I use at the moment.

Since my posts last night I have removed and reseated the block and now the heat up is gradual, in fact I seem to be maxing around 36c and it takes a good 30seconds to get there - so perhaps I have resolved 1 problem.

With regards to my choice of 10mm - that is what my entire loop is based around - I may look into replace the tubing and connectors with 1/2", but after my recent Opteron purchase I cannot afford to replace the whole loop.

Think I will invest in a Storm and a Black Ice Xtreme 1 for now and see where I get.

Thanks ever so much for everyone's comments, really appreciate your time.

The asetek block really isn't that bad:

http://www.overclockers.com/articles373/wbsum.asp

It's actually pretty good, in terms of performance. For weaker pumps and smaller ID tubing its actually darn close to ideal. Too bad they use acrylic

Of course I havent heard of many cases where the tops crack. I think thats just because not as many people have asetek blocks compared to all those that have acrylic toped DD blocks.