Pumps in serial: DDC vs D5

Basis physics, higher the pressure the harder to migrate temps. You don't want to kill your loop by forcing too much water over the components as its not effective. You're running cool water over a hot component without hardly any heat exchange. You're running hot if you think you need that much flow.

Pretty much can back that up, I've my D5 running at only 4000 rpm (60%) and my loop it basically room temp with a 4.4ghz 5930 and a 980 in it. Faster isn't better. A constant speed and lower pressure means higher ability to transfer heat to water and to the radiators. Otherwise you're just ****ing into the wind.
 
Cerelia said:
Pretty much can back that up, I've my D5 running at only 4000 rpm (60%) and my loop it basically room temp with a 4.4ghz 5930 and a 980 in it. Faster isn't better. A constant speed and lower pressure means higher ability to transfer heat to water and to the radiators. Otherwise you're just ****ing into the wind.
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http://www.overclockers.com/watercooling-myths-exposed/

Myth: Water must slow down to fully absorb heat.

Reality: In a closed loop, a given water molecule actually spends
the same amount of time in the radiator, no matter how fast it is
moving, as long as the water is indeed moving.

If this is a difficult concept to understand, think about a race car on a track.
If the track is one mile (5280 ft) long and the car is driving at 60
mph, the car will spend about one second in a 100 ft stretch. Think
of the 100 ft stretch as the radiator.

If the speed is doubled, the car only spends ½ a second in the 100 ft section, but
it passes through that same section twice a minute, so it spends a
total of one second in the 100 ft section per minute.
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^ Not necessarily true. A higher mean residence time spent in a heat dissipation zone before it passes through a heat collection zone is good. At the same time you want the coolant to flow though blocks fast (at least with blocks that scale in performance with higher flow rate, there are some that don't scale well or are best at lower flow) so it's a bit up there.

That example is a terrible one because the race car of the track example isn't influenced by different stretches of the track. Say one part of the track has potholes and the other is smooth and paved, the race car and driver would experience different things at the different sections.
 
vsg28 said:
Ah so you have voltage control via 3 pin fan header?
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I fitted a PWM plug but it only in a 3 pin header right now, i have it set to constant 90% and it silent, when i had it in a pwm header it was run by the CPU and the SLI Gpu's would get hot when the CPU wasn't under load.

Set the pump to 100% and put it on a soft pad. if its still loud you have a bad pump, or i have a very good one :D
 
P4Clock said:
no 1t the base model, you can mad a 1t to use a fan plug then put it into a fan header on the mother board and your golden.

mine as a PWM board you will ever have a pwm board or a 18w board you should look into it.

but onto been quiet, mine made one hell of a lot of noise when i got it, but putting it on a pad fixed it.
try putting yours on a something soft, ever at 100% it a lot better.
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I'm sorry but what you said is confusing, can you tyoe it again?

vsg28 said:
So what cables are on the pump? Just a full size Molex?
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Mine are the fan headers, came stock like that.
 
almighty15 said:
I'm sorry but what you said is confusing, can you tyoe it again?
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What i was saying is you can modify a base level pump into a better pump, most of the pumps are 18w.
Open your pump up and have a look at the PCB. ever DDC made is ever an 18watt or PWM. just because your is only as standard input dont mean its a standard pump.
My pump came from OcUK as a DDC 10w 1t(Bottom level pump) but the PCB is a 3.1 PWM, so i removed all the standard plugs and fitted an PWM cable:)

second problem is the noise....
i have the normal pump running at 90% speed 3000rpm and it is silent, you need to put your pump on a pad of some sort, i have mine sitting on a sponge for a few weeks till i got something better for the job but it made no noise.
if you have low flow put the pump on 100%, and pad it.
 
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Not trying to be facetious, but you guys seem to be over thinking things here, no?

I connect up my loop, put the pump on full pelt. I then stress the system to get maximum temps. When values are confirmed acceptable, I lower the pump speed and continue to test. Then repeat, and test...

My pump is currently at its lowest, silent setting. Temperatures are fine.
 
P4Clock said:
sorry thought it was your OP for a second :P
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Makes sense now!

I'm really just wondering why the OP needs the 2 pumps for a target flow rate... surely acceptable temperatures are the target? If they can't be achieved, then investigate why by all means, but the OP has not mentioned poor temperatures?

As I say, I'm just interested in the thought process.
 
P4Clock said:
What i was saying is you can modify a base level pump into a better pump, most of the pumps are 18w.
Open your pump up and have a look at the PCB. ever DDC made is ever an 18watt or PWM. just because your is only as standard input dont mean its a standard pump.
My pump came from OcUK as a DDC 10w 1t(Bottom level pump) but the PCB is a 3.1 PWM, so i removed all the standard plugs and fitted an PWM cable:)

second problem is the noise....
i have the normal pump running at 90% speed 3000rpm and it is silent, you need to put your pump on a pad of some sort, i have mine sitting on a sponge for a few weeks till i got something better for the job but it made no noise.
if you have low flow put the pump on 100%, and pad it.
Click to expand...

But how are you running them at 90%??

Mine are already the 18w versions.
 
String said:
Makes sense now!

I'm really just wondering why the OP needs the 2 pumps for a target flow rate... surely acceptable temperatures are the target? If they can't be achieved, then investigate why by all means, but the OP has not mentioned poor temperatures?

As I say, I'm just interested in the thought process.
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It's widely regarded that you need above 1Gpm for optimal performance, not to mention it makes bleeding and getting air of the loop a heck of a lot easier.

I have a very restrictive loop and it's took no where near the amount of fluid that it should be taking, the pumps are just to damn slow to push the air out.

Moving the case doesn't help either.
 
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