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optimum dual pump orientation and dual gpu

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May 21, 2013 7:01:29 AM

ive got two seperate questions as i'm reduing my barely operating xspc rasa 240rs kit loop, thanks to its bad from day 1 750 pump.

i've already purchased two identical pumps to replace the 750, because getting an RMA from XSPC is as possible as teaching an donkey to fly by dropping it off an cliff, miracles happen but its unlikely.

as you probably figured from previous prgh. i've decided to go with an seperate pump/res unlike the combo ive got for redudancy reason. but immidietly came to me the question, how to orient the two pumps? directly to one another / one directily under the res, and the other... like.. after the cpu and rad, with the rad acting as 2nd res? this way instead doubling the psi the pump combo will handle, the other pump actually will act as an inline flow amplifier, but how will the performance differ? anyone tried this?

2nd question is about gpu wc, i've got xfire hd9750 setup with none WC yet, thanks to the barely cpu only handling 750, but ive also got an raystorm GPU handy, but is it logical to WC just one gpu? like.. the main one? also ive got two diffrent versions, one with greater cooling solution but higher noise, the other wth 3 fans but worse cooling and quieter.

which would you suggest to WC if 1 cooling 1 is feasable option? else i'll probably get another raystorm gpu.

thanks lads.


PS i'm not unsatisfied with XSPC nor with its services but you should know getting replacement from them requiers you to prove the iem in questuion has either exploaded / fried. else they will simply pin it to user fault.

JJs
a c 177 K Overclocking
May 21, 2013 7:29:10 AM

Can feel your pain about the X20 750, just recently upgraded from one myself as I was concerned it was a bit weak to handle a GPU+CPU loop. Thankfully it didnt die on me, so I'v got some level of redundancy if my Koolance fails.

You definitely want the pumps in series with each other, having them in parallel has such little performance benefits and if one fails then you lose the majority of your pumping power.
http://martinsliquidlab.org/2011/04/26/pump-setup-serie...

I would just have both immediately after the reservoir in the flow order, the less chance of a pump running dry the better. You could have the pumps distributed through the loop, but again in that situation would use a 2nd reservoir to make sure it doesn't have air run through it.

I think water-cool the card on top, as that would have the most inhibited airflow of the two.
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May 21, 2013 7:45:55 AM

Thanks!

you misunderstood the orienattion ques. its not parl vs ser. but series pumps directly to each other vs ser with pump distrbted through the loop so the other one is after the cpu and rad which acts as 2nd res.. will it be more beneficial either way?

thanks JJs
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a c 103 K Overclocking
May 21, 2013 7:50:37 AM

The gents here helped me avoid that x20 due to this exact thing... oy... another bites it...

Manochalk dead on as usual. Series - functions as booster and backup. Placement not overly critical, so eitjer both right after res, or as mine little further down the loop at a low spot and boosting up to a high mount rad for head pressure.

Top slot is "usually" the primary use card. Certain boards - e.g. asrock extreme11 in tri sli - can use a lower slot as primary. WC whichever is the hot/ primary. And save for a second lol
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a c 103 K Overclocking
May 21, 2013 7:54:07 AM

In my example I have res> pump> cpu> rad> gpu> gpu> pump> rad> moboblocks> ram> pump> rad with pumps running under max on all - setting 3 on mcp655

Im alsi dealing with a 2ft run every rad (mountain ascension extended case) so need a bit more pressure n flow to compensate and still a bit overkill. So something similar on a 2 pump setup like yours would more than suffice
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May 21, 2013 8:30:55 AM

Buzz247 said:
In my example I have res> pump> cpu> rad> gpu> gpu> pump> rad> moboblocks> ram> pump> rad with pumps running under max on all - setting 3 on mcp655

Im alsi dealing with a 2ft run every rad (mountain ascension extended case) so need a bit more pressure n flow to compensate and still a bit overkill. So something similar on a 2 pump setup like yours would more than suffice


thats an great example, thank you, so according to you, its diffrent in an loop ike mine both orientation will produce near similar performance? btw i'd probably should note i've got another xspc 120 RX which is about as heat-capacitive as the 240rs due to its higher depth.

so the loop will be as following either:

res>pump>cpu>240rad>(+mini res?)pump>120rx rad>gpu>back to res.

res>pump>pump>cpu>240rad>120rx rad> gpu> back to res.

any practical diff between the two loops? BOTH are series pump.

thank you,

JJs
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a c 103 K Overclocking
May 21, 2013 8:55:59 PM

Id swap ur run for gpu> rad> res otherwise ur pumping hot into res and back to cpu.

You could go cpu> gpu> rad> rad too. No differential there and fully cooled before next loop

Either pump placement works. As a general rule, dont send heated hater to pump w/o going thru a rad, or to res
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a c 177 K Overclocking
May 22, 2013 12:06:22 AM

It wont make any real difference if your pumps are together or spread through the loop, do whichever is convenient I guess.

About loop order and putting rads between blocks and pumps and all that, don't bother. On a loop of your scale, and in general, it will make no difference. I have a similar loop (admittedly way more rad space though) to what your proposing, and I have the CPU feeding water to the GPU. GPU temp (at idle and load) doesn't change if the CPU is under load or not. The water (especially in your overkill pump loop) is moving too fast for it to make a difference, the water will eventually hit an equilibrium temperature and sit there.
There is some benefit to making sure just cooled water hits your blocks, but your talking a degree or two at most, if it makes a difference at all.

Also while on the topic of pump cooling, if you get DDC pumps make sure they have good airflow over them. Unlike D5 pumps they arent cooled by the water that goes through them. Annoyingly at stock they dont come with heatsinks, but still put some airflow over them.

EDIT: also Buzz, thats a pretty awesome case :D . Dual systems?
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May 22, 2013 8:42:52 AM

Mr Chalk. Thank you ALOT! you solved all the questions ive had about this.

I'm gonna go with the res>pump>cpu>rad1>pump>rad>gpu>back to res.

the reason for that is simply because its easier to actually route the tubings not to get 'cooler/warmer' water to designated zones as i'm well aware that water temp reaches an equilibrium that simply doesn't change throughout the loop. not in our size scales at least.

otherwise, thanks buzz too! you've been great help as well, but careful with the misleading info there about water temps etc, cause its incorrect.

case solved. best answer is the ^chalks, how do you select that, im not sure.

thank you guys,

JJs
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a c 103 K Overclocking
May 22, 2013 9:15:28 AM

Glad we could help. And no, not misleading info. In fact accurate to a fault. Manochalk mentioned it will make a difference just not much. Not being able to see your exact build, I chose to err on side of caution. Manochalk gave you a very practical answer that is viable in majority of situations. Im just a very picky person and firmly believe in overradding and max cooling efficiency. Lol. Yes it will reach equilibrium. My POV is based on the thought, if I can get that equilibrium a couple degrees cooler then more headroom for OC, and better component longevity. Water coming from primary heat source, without hitting a rad first, to a res will decrease time to reach equilibrium, and increase equilibrium temp, no doubt about it. A couple degrees? Yes. But I am picky like I said. So ideal is not always viable for some. Bear in mind - your title asked for "optimum", not viable - I answered accordingly

@man not dual - yet... running 3x 480 1x 360( all rads Alphacool Monsta 80mm with technofront airboxes - had to mod 240s to work) 3x mcp655. Told ya I love overkill lol. Once I go dual will be adding and moving rads to a water brrl 24
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a c 177 K Overclocking
May 22, 2013 11:34:30 PM

Just route the tubing in the way that looks best and uses the least amount of tubing. Preferably don't let tubes cross, doesn't look that great. A water-loop should look like a loop, not a pretzel :p .

And here I thought my dual 360mm rads were overkill :o .
Have you considered going Peltier cooling?
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a c 103 K Overclocking
May 22, 2013 11:38:14 PM

Contemplated - not ready to take the plunge just yet nd LN2 overkill for even me lol
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