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Unread 12-07-2004, 04:51 AM   #155
Cathar
Thermophile
 
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Join Date: Sep 2002
Location: Melbourne, Australia
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Quote:
Originally Posted by nikhsub1
THe question at hand is at what voltage yeilds the best overall temps?
That really depends on how much heat the CPU is putting out, and how well your radiator is working.

A hotter CPU will benefit more from a hotter/stronger pump because the temperature delta bonus from the increased flow rate is greater with the hotter CPU.

The better the radiator, the stronger and hotter the pump can be without the water warming up by much. If the radiator had a theoretical C/W of 0 then you can stick a 1HP pump on there if you wanted.

Given your setup though, with a hot CPU and a strong radiator setup, you will be able to run the RD30 at 24v or even 26v and still see better temps, but overall I think you will basically witness a near plateau (~0.2C variation) between giving the pump 20v up to 26v, in which case you may as well just use 20v and be sucking down less power. Give it a go.

Even with my present 2 x D4's and the big 30x24cm radiator I see CPU temps plateau between 12-14v on the pumps, and above 14v the CPU temp will start to climb as the water starts to get a lot warmer.

Quote:
What is the power draw at 24v and would the extra flowrate at 24v be negated by the additional heat? Also, may be a dumb question but are there any reprocussions of undervolting the pump? Now I'm really itching to get mine installed.
Haven't measured power draw at 24v yet. My estimate would be around the 50W mark. I'll measure it when I next get the chance.

Should be no repercussions with undervolting so long as you're not right near the point where the electronics are struggling and the pump starts stalling. Really anything at or above 14v should be fine.
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