Pump pulling from CPU does it make a difference?

[bluehaze]

New to watercooling, picked up a bunch of stuff to try it out.

Have a magicool elegant 360 radiator
Koolance 350 cpu block
ddc 3.25 with an xspc top
ek waterfall res
Bitspower compression fittings for tygon 1/2 id 3/4 od

The cleanest loop for me is pump>rad>res>cpu

Is this bad? If so what is the best way to route it?

This is on Evga Classified with 17 920 d0.

Also was thinking of getting 2 gtx 295 or 3 285 and adding those to the loop in the future, would it be too much for 1 360 rad and 1 pump? I prefer to keep the build clean so only want to use 1 rad if a normal 360 rad is not able to keep up would something like the monsta 360 be up to it? Don't really care about the price of it if it would help that's all I care about.

Also using Thermalright 1600 rpm fans because I had 2 already so just purchased a third haven't decided what fans I will end up running but these are quiet and push alot of air for the lack of noise they produce so I like them, although haven't heard them through a radiator yet.

Edit: Also using Primochill PURE coolant for convenience, not sure where to get distilled water, can go with distilled though if it will make a significant difference in temps?

[Sadasius]

Welcome! One thing to know is to always have your res before the pump. Pumping water into a res is a waste because you lose all your pressure. Usually the res is the end result of a loop before beginning again. It feeds the pumps. The Koolance 350 CPU block is a highly restrictive but excellent block. You want to have as much power and pressure as you can directly into it. So with that we will have this as the end result of a performance loop;

Res-->Pump-->CPU-->Rad-->Back to Res

Also was thinking of getting 2 gtx 295 or 3 285 and adding those to the loop in the future, would it be too much for 1 360 rad and 1 pump? I prefer to keep the build clean so only want to use 1 rad if a normal 360 rad is not able to keep up would something like the monsta 360 be up to it? Don't really care about the price of it if it would help that's all I care about.

Sure if you want no OC on the CPU. Temps will not compare to more efficient loops but it can do the job. Hopefully soon we will see some numbers on the MONSTA to be able to determine if it's the 'best' rad as they claim.

[bluehaze]

Thanks, will work on rearranging loop then, I originally was trying to set it up to have the pump go directly into cpu but was told to have pump go through rad first due to the heat produced from the pump. So this is not the case then and the Radiator should not be in between the pump and the cpu?

[Vapor]

You want to have as much power and pressure as you can directly into it.

I disagree.

A component's (block or radiator) thermal performance directly relates to flow and flow alone. Flow directly relates to the balance of pumping power and net pressure drop from the combined components. Ergo, the performance of a block in no way has to do with where it is positioned in the loop (except that temps vary slightly throughout a loop, depending on components and flowrate). Each component will have the exact same pressure drop no matter where it is in a loop.

As for the reason we put the res immediately before the pump? It's much, much easier to bleed that way.

To the OP: with a CPU-only loop with a good pump, order is basically irrelevant, small fractions of a degree between best and worst....just put it together in whatever looks the best is my vote (and res before pump since it's easiest to bleed by a lot....and if you do want that last .1C, put the radiator directly before the block)

[Sadasius]

Vapor.....So your saying turbulence in a block does not have any benefit?

[Vapor]

Of course it does

But the pressure drop of a component is constant no matter where it is in a loop (so long as the other components do not change).

Turbulence relates to the internal structure of a block and flowrate.

[Movieman]

snip~

Res-->Pump-->CPU-->Rad-->Back to Res

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

[JOCKTHEGLIDE]

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

thats what I learned here was res, pump, rad, to cpu.......also

[Vapor]

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

Unless this pump is very bad (it's not) and/or this CPU is a monster (400W+), the difference is very small (less than a degree even with 400W and a 'meh' pump, only really detectable from logged results of CPU and ambient temps)...but I agree it's still a positive difference nonetheless

[Snyxxx]

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

While this is technically correct, the usual difference in temperature after steady state equilibrium is maybe 1~2° C between entrance and exit of radiator.

Every little bit helps, but it has to be taken with the grain of salt. A different configuration that results in cleaner tubing runs may negate the "rad to cpu" path if desired.

[Waterlogged]

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

Water is within 1°C through the entire loop after equilibrium.

About the pressure thing, if the rad is between the pump and CPU, the water loses X amount of pressure (whatever that rad is rated for) to create turbulence. Flow rate is constant, pressure is not.

[Vapor]

Water is within 1°C through the entire loop after equilibrium.

About the pressure thing, if the rad is between the pump and CPU, the water loses X amount of pressure (whatever that rad is rated for) to create turbulence. Flow rate is constant, pressure is not.

It will have the exact same pressure drop no matter where it is in a loop.

If a pump produces 100 units of pressure (at the flowrate of the given loop), the rad has a pressure drop (at this flowrate) of 20 units, the res has a pressure drop of 5, and the CPU block a pressure drop of 75, it will be 75 no matter where it is in the loop. X units of pressure will exist at the intake and there will be X-75 units immediately after the block.

Doesn't matter if the order is 75-20-5, 20-75-5, 5-20-75, or whatever. The pressure drop of any given component is a given curve like these:
. That curve doesn't change depending on where it is in a loop. Therefore, the pressure drop doesn't change depending on where it is in a loop, therefore the flow doesn't change, therefore the performance doesn't change.

[Movieman]

To all the guys above:
I realise it's a small difference but my logic is this:
Your planning a water cooled system, why not do it the way that gets you every possible advantage even if that advantage is only 1c or .00001C..
Better is better right?
Same labor to build so get all you can.

[Vapor]

To all the guys above:
I realise it's a small difference but my logic is this:
Your planning a water cooled system, why not do it the way that gets you every possible advantage even if that advantage is only 1c or .00001C..
Better is better right?
Same labor to build so get all you can.

From a performance point of view, you definitely put the radiator right before the block....but if that means awkward tubing routing (an aesthetic thing), sometimes it's not worth it to everyone.

[Sadasius]

Hmmmmm, after the rad or not after the rad, that is the question! Now I would like to see testing to finally put this one to rest! This has been one of those things like negative and positive pressure in a case deals. People are going to continue to conflict unless there is absolute test results.

[ben805]

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

+1

That's how I setup mine.

[JOCKTHEGLIDE]

From a performance point of view, you definitely put the radiator right before the block....but if that means awkward tubing routing (an aesthetic thing), sometimes it's not worth it to everyone.

even with all the fittings these days it cant be that akward

[alexjpn]

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

+1

the order does not change the factor. (pressure)
if the circuit is in a single loop

[bluehaze]

Well got it all setup, got res>pump>rad>cpu, only problem I'm having is ton's of foam the water turns white when the pump is on from all the foam. I've been stopping it every so often and refilling the res letting all the foam overflow out of the top and have gotten rid of most of it but its a real PIA because the foam keeps getting sucked back out of the res and through the loop again. Water went from solid white like milk to now is just cloudy. Need to go to bed gonna let it run while I sleep and see what happens.

[Jamesrt2004]

surely foams from air etc and pums just mixing it? maybe air still in the rad thats coming out etc.. ??

(I think)

[Mekrel]

Reservoir before pump, in order to prime the pump easily and bleed. Component order, what ever gives neat/shortest tubing is the way to go in my opinion.

Order will not make a difference as Vapour said, well nothing that we can really measure without stupidly calibrated/accurate thermometers.

[Easybeat]

Component order, what ever gives neat/shortest tubing is the way to go in my opinion.

I pretty much agree with that, I tried 2 configs for my setup and the results were identical near as dammit.

Firstly and the one I stuck with as the tubing was a lot shorter.
Pump - Radiator - GPU - CPU

And the one I didn't use.
Pump - CPU - GPU - Radiator

[kinghong1970]

correct me if i'm wrong... but as to the original question... can pump PULL from CPU... well iirc, the pump needs a steady supply of water but it really does not have any "pulling" power... hence res is always before the pump and providing constant supply of coolant to it.

it seems that it works best if pump was located to push water through the loop and dump at a reservoir...

just some naive observation...

OP, as for foam, did you clean out the radiator?
i noticed some foaming when i used some coolants such as the swiftech and primochills... but in distilled, no fizz... no foam...

let it run a while and see if it clears.
i too have read somewhere that the temp in a loop pretty much normalizes...

[Hondacity]

Hmmmmm, after the rad or not after the rad, that is the question! Now I would like to see testing to finally put this one to rest! This has been one of those things like negative and positive pressure in a case deals. People are going to continue to conflict unless there is absolute test results.

this is really predictable...after one hour the cpu has raised the water temp for both setups at the same temperature...

with good flow the water temp at any point of the loop wouldn't vary...

imagine less than 300ml(total liquid volume) for a normal setup(small res)...with a flow of 8lpm every 2.5xx seconds that 300ml would have gone thru the loop completely...

my assumption is that it would be the same for both setups

[NaeKuh]

I disagree..
Res-->Pump-->Rad-->CPU--> Back to res
you want your coolest water entering the cpu and that is always going to be the water coming out of the radiator.

nah eric and dave... sadius is correct when it comes with the KL-350.

trust me ive had too much time on the bed with it.

Pump right b4 kl-350 on this block guys.