Theoretical loop order

[IceShock]

okay guys, heres a image of the side of my pc that I edited, I have a H110 at the top which is 2x 140mm fans, and I edited the picture to pretty much where I can install rads etc well yeah anyway.

Iv thought a few times the best possible way of doing a custom loop in my rig, and whilst motivated by a few beers iv come up with this.
Now hear me out, I don't know that much about custom loops, but here is my Theory, (correct me if I am wrong) but, I thought it would be best to go like this.

(this idea, I will not be using these current specs, its for when I upgrade and go for say maybe two 390x gpus, and a nice 6core or 8core cpu)

420rad@top of case > cpu > gpu 1 > 280 rad > pump > gpu 2 > 420 rad.

(yellow box on picture = the tube style pump res thing that costs a arm and a leg)

I priced it up on ocuk, it would cost around 500 quid for the loop. but im posting this asking, is that the right way to do a loop for the best temperatures, because though im no water cooling expert, even i know that the size of a gpu block and the heat a gpu produces well, in my picture, gpu 1 will = around the same temperature as gpu 2, because gpu 1 is linked to a bigger rad but has a cpu warming the water before hand, there for cancelling out say half of the cooling provided by the 420 radiator if that makes sense, then the gpu 2 only has a 280 rad cooling it.

that's my theory anyway, correct me if im wrong, by the way im not bothered 100% about the looks and tubes all over the shop, just about the best performance for my pennys.

But if you guys can edit my picture and show me a better way of doing it or something, feel free thanks and advice is welcome. like I say this will be in the future not yet.

also, I learnt a few things when pricing up the bill, as im a water cooling noob, I learnt about the hose diamiters and outer diamiters etc, there seems to be two standard sizes, (cant remember off top of my head) but im guessing the biggest is the best? but iv tried to google one vs the other but cant find anything at all, not even pictures so no idea how the thickness and width even looks so any helps welcome.

thanks again

edits: the front rad would be intaking cold air into case not pushing as the picture suggests that's just a MS paint fail there. and the dvd drive bays would be cut out (and if it measured up and fitted, a 320 or another 420 would go there). also my gpu2 wouldn't be tilted like it is in picture

 

[Mynight]

You can place the loop in any order you want as long as the res is before the pump to allow a constant supply.

Putting rads between components will provide negligible improvements over any other order.

Choose what looks best.

As for tube sizes smaller ones allow for tighter bends but increase restriction and increase risk of pinching the tube. Larger ones allow less restriction with less chance of pinching but require more space for bends.

Unlikely to cause issues with a decent pump but lower restriction would allow you to run the pump quieter.

There's many tube sizes personally I use 16/10mm as its the middle ground.

 

[IceShock]

this is the res pump id use, measured it it fits like a charm.

http://www.overclockers.co.uk/showproduct.php?prodid=WC-272-XS&groupid=962&catid=2133&subcat=1845

XSPC D5 Photon 170 Reservoir/Pump Combo

okay, so the loop order makes no difference to temperatures at all?

so a loop of: Cpu>gpu1>gpu2>pump/res>280rad>420rad
would cool each gpu and keep every thing simerlar temperatures as.
cpu>gpu1>280rad>pump/res>gpu2>420rad

and as you say a pump defo has to come after a radiator, but if it has a res built into the pump, does that rule out that rule? so to speak.

thanks

 

[Mynight]

Sorry I meant to say res not rad in the previous post.

As long as the res is before the pump all other components can go in whatever order you want.

The difference between those loops would be minimal at best probably not even 1 degree. Theres a scientific explanation but I'm too tired to remember what it's called sorry. Basically the water in the entire loop will be at pretty much the same temperature at any point you measure. Iirc when I was playing with a temp probe the water in vs out of the cpu block was within .3 degrees.

My setup currently is pump/res>cpu>rad>gpu>rad>back again. As it was the cleanest run.

The D5 is a great pump its powerful enough that you can use whatever tube you want and it won't struggle.

 

[IceShock]

Ah, I see, that kinda makes sense. because all the water in the loop is linked together, no matter where the source of cooling comes from at which points they are situated at, the water will maintain a average temperature of water throughout the loop because its all every water partial is connected to each other. well making contact with should I say.

But before I say to my self, Duh why did I say such a stupid question when the laws of physics situates that the average temperature will be the same, surely a rad between the two gpus rather than the 2nd gpu being fed hot water from the cpu and gpu 1 to gpu 2, surely a rad between must show some impact at all.

Because the rate that water cools down (via a rad cooling water then the cold water particals spreading backwards through the loop) surely cannot spread backwards quick enough in the opposite direction to the hot water flow to cool gpu 2 better than a rad between the the two gpus could?

 

[andybird123]

The temp of the water in a loop with decent flow will be about +/- 1C
The shortest loop will have the best flow, so by sticking a rad between the two gpus will at best get you 1C better temperatures, but could adversely affect flow rates

Cold water particles dont travel backwards, but the flow in the loop should be so fast that min and max temperatures are not very far at all from average

There is always water in the blocks taking up heat and there is always water in the rads dumping heat to air, so as long as you have enough rad space to dump enough heat, the water temperature will reach an equilibrium and will stop climbing

I have a cpu and three gpus in my loop, my water temp is usually 4C over ambient and my water out of the last gpu is 1C above water coming out of my rad... My last gpu is not my warmest as block and mounting differences make a bigger difference than water temp variances, and all of my gpus stay under 45C at all times, even in the hottest weather

 

[BluD]

Mine goes CPU-GPU-GPU-240-pump-360. I just set mine up so it was the easiest way to run the pipes and bleed the air. My second GPU ran a couple of degrees hotter when i ran them in serial, i run them in parallel now though to get a better flow.

 

[IceShock]

Alright that all makes sense cheers guys I guess I'd just go cpu>gpu>gpu>res/pump>280>420>cpu

And there would be half as much tubing

Thanks again