**Restriction Testing**

Continuing the same test method as before, I’m measuring restriction or pressure drop over the range of possible flow rates to get a complete look. I simply increase flow across the radiator at .5 GPM increments and record the pressure drop across the rad via manometer. My flow meter is a King Instruments 7520 with valve, my manometer is a Dwyer 477-5 digital manometer, and I have fabricated my own 1/2″copper x 1/4″ brass T fittings to avoid adding restriction to the test.

Radiators are generally pretty low in restriction, so this is normally not something to worry about much unless you plan to run several radiators in series.

First the detailed results:

Followed by a comparison:

Restriction is a tie for first with the RX360, the results were identical. Very nice! No worries at all about restriction, you could run many of these in series without even approaching the restriction of even a low restriction CPU block.

As a follow up …..

http://www.madsci.org/posts/archives/dec2001/1009665868.Cs.r.html

“Lets say that you have three servers, each consuming 300 watts of

electricity, and a monitor producing 100 watts of heat. So the heat load

from the electrical equipment is 1000 watts total. Now it is true that a

few watts of power exits the room in the wires, but essentially all of the

electric power that the equipment uses is converted to heat.”

See also http://www.overclock.net/t/126350/heat-from-cpu-w

Finally, you’ll also note that plugging anything into the PSU calculator

http://extreme.outervision.com/psucalculatorlite.jsp

and for determining ya heat sink size

http://www.extreme.outervision.com/tools.jsp

give the exact same number

It is true that there are heat losses through the motherboard, but there are also significant cooling losses with heat recirculation, dust, and air flow restrictions. Even more important is the actual loading in real world use vs. synthetic testing. Any amount of heat/cooling planning is good enough, don’t get too caught up in the being exact.

Certainly true …. I make that point often over on OCN….. I always calculate the numbers and find out what the math says should be the number. That’s the idealized goal :)…… then we get to reality. As I remember the radiator sides / shroud is not accounted for in your graphs….there’s also the res, tubing, fittings all of the components, backplates, etc.

So once I get the number for the 10C “ideal”, I look at what can realistically fit and look for the most cost effective / realistic alternative. In my current build, at 1250 rpm, I can exhaust 62% of the idealized heat output thru my rads…. this creeps up to 87% at 1800 rpm. At real loads….I think I’ll ever tax even the 62% loading.

Hi Martin,

I am going to build a liquid cooled rig, let’s say with several 7990.. It is better to rely on a single massive radiator like the mora 3 pro (9-18×140) or several smaller like this one, the ut60 360?

I guess the first solution is the most efficient, but the second one has the advantage to insert a radiator between some gpus..

What do you think?

Hi Martin.

Considering the very linear curve of the UT60 performance, would it be fair to assume 600 w ofcooling at 4000 rpm (twice that at 2000 rpm and 4 times that at 1000 rpm) ?

Hi Martin.

Considering the very linear curve of the UT60 performance, would it be fair to assume 600 w ofcooling at 4000 rpm (twice that at 2000 rpm and 4 times that at 1000 rpm) ?

And what cooling power would you estimate at 4000 rpm in push/pull?

I can’t imagine being in the same room w/ 4000 rpm fans, I can’t be in the same room with a H100 and it’s 2,600 rpm fans due to the 60 dBA vacuum cleaner level equivalent sound.

As for cooling, martin would know better but from my experience with building ventilation, after a certain point, the air resistance and turbulence brings a point of diminishing returns.