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Cooling The current obsession with dual loop WC

Discussion in 'Hardware' started by ataraxis84, 18 Aug 2010.

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Dual Loop or Single Loop?

Poll closed 1 Sep 2010.
  1. Dual Loop

    6 vote(s)
    21.4%
  2. Single Loop

    22 vote(s)
    78.6%
  1. ataraxis84

    ataraxis84 What's a Dremel?

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    Hi guys/girls,

    Just wanted to get everyones collective thoughts about the dual loop revolution we seem to have been going through for the last little while.

    Why is everyone so obsessed with going with 2 seperate loops, even to the point of saying to someone who wants to cool 2xGPU and CPU "you'd be pushing it with a single loop, better go dual".

    It is utter rubbish, I've been watercooling on and off for years, and at its height was cooling NB SB 2x7900GTX RAM and CPU off 1 loop with no issues at all with temps, they were all in and around 30degrees which is where I expect them to be.

    Currently I'm only cooling a 9800GTX+ (Mild overclock, basically as far as I can go without voltmodding it) and an x6800 core2 (currently sat at 1.42V at 3.6GHz, have had it at 1.6/1.7V at 4GHz+ without major temp issues) using 1 360 Rad and a 120, 1/2" ID tubing D5 Vario pump (god that thing is lasting well) and with ambient temps just under 20degrees I see about 25idle and late 30's whilst running prime 95 on large FFT's.

    So I suppose the real question is why people are knocking single loop watercooling so badly. Is it just because its the new 'in' thing to do, and as a result people are poorly educated or is there more to it?

    I recently read an article, http://www.xtremesystems.org/forums/showpost.php?p=4451170&postcount=1 and the general consensus seems to be that although having dual loops can drop temperatures by a small margin (not worth the extra cost in double pumps/special resevoir etc) at high load, but can leave you with unused thermal capacity in one of your loops, and a 'thermally capped' second loop where single loops don't suffer with this at all.

    Again, this also feels like miseducation, but a great deal of people seem to think that you get big differences in temps at different stages during a waterloop. This is so far from the truth as the water in the system will always reach a point of equilibrium so any increase in one components temperature will only affect another because it can increase the temperature of the loop by say 1degree, using up some of the thermal capacity of the system.

    I appreciate that it might look really good, but it just seems like I've seen a lot of people giving what I personally see as bad advice (not necessarily here, but across a number of forums), and wanted to see what the collective thoughts were and make a constuctive post to help give people food for thought.
     
  2. Sh0cKeR

    Sh0cKeR a=2(s-ut)/t²

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    I'm running two single loop systems at the moment and their temperatures are stellar. Dual loops means another pump, and it just adds to the massive vibrations in the case. Too much vibration, and you get an annoyingly tonal, resonating metal hum that drives you mad. Plus, you can always fight the higher water temperatures by adding more radiators.
     
  3. SlowMotionSuicide

    SlowMotionSuicide Come Hell or High Water

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    Though I only got CPU in single loop atm, I'm going to add GPU later but not planning to go dual at any time. I too saw Gabe's article some time ago at xs. Too bad the place is showing a bit too much drama to my liking lately.

    Guess it looks pro having lots of tubing and equipment in your loop. And like you said, there seem to be whole lot of misconceptions about thermal dynamics in watercooling loop. Not only that, but there's some strange ideas regarding fans and movement of air as well.

    Also, it might have something to do general obsession of "having the greatest numbers" so to speak. People are willing to go great lengths to eke out the few remaining MHzs out of their chips, ("upgrading" 920 to 930 since it's better overclocker comes readily to mind), even if preciously few of us can even begin to fully utilize 4 GHz quad cores, so I guess it's natural to only consider the best possible combination, even if the difference is few degrees.
     
  4. ataraxis84

    ataraxis84 What's a Dremel?

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    I do find it funny though, as thats where the original post was made by gabe, and yet its also one of the worst for dual loop bad advice..... seems people fail at reading and digesting information.
     
  5. brave758

    brave758 Minimodder

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    Well said :clap:
     
  6. ataraxis84

    ataraxis84 What's a Dremel?

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    Added a poll to get peoples thoughts
     
  7. Combatus

    Combatus Bit-tech Modding + hardware reviews Lover of bit-tech Super Moderator

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    Single loops are my preference. Unless you have a CPU block which relies heavily on turbulence and is very restrictive, then modern pumps are more than capable of handling a loop with CPU, GPU, MB blocks and a couple of rads.

    As is alluded to in previous posts, the likelihood is you'll end up with excess thermal capacity in one loop - it's far better to have all your rads and blocks in one loop working together.

    I think it partly stems from the misconception that coolant is massively hotter after it leaves the first block so people want to separate things. This is totally wrong - you're looking at a few degrees in the delta T between water in and water out at most, due to the specific heat capacity of water (it takes a lot of energy to heat it up) and the speed at which the coolant is travelling round the loop. This has a tiny effect on absolute temperatures of your hardware.
     
  8. Chris_Waddle

    Chris_Waddle Loving my new digital pinball machine

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    In my current build I went down the route of 2 loops and I hardly noticed any difference (apart from need a heck of a lot more room in the case for pumps etc).

    I'm now in the process of building my new machine and am going back to a single loop. As I will end up with a complete watercooling system left over (apart from a cpu block), I've decided to watercool my 2nd pc.

    For me, the two loop system was a waste of money for the small performance gain. I won't be making that mistake again.
     
  9. Arthur

    Arthur It's for 'erberts !

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    2 loops :)
     
  10. SPNKR

    SPNKR Pretty Good Kid

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    Am I also alone in thinking that people really go overboard with radiators too? I mean a three fan radiator I would think is enough for just about any loop barring three graphics cards or whatnot. I mean I'll be honest, I don't have any real watercooling experience (I have a Corsair h50, but you really can't class that even as watercooling), but I just see some of these builds with like a quad radiator on top, a dual on the bottom, and a triple hidden somewhere else.

    According to wattage, which I know is not always right, but is a good guestimater at least, you should be able to run a CPU/Graphics Card/Mobo off even a twin rad single loop getting decent temps. Am I right in this, or am I full of crap? :)

    But I definitely agree with the single loop deal, unless you are running four graphics cards, an SR-2 build, or a combination of the two, there really is no advantage to running two loops, especially since the extra pumps and hardware translate into more noise, heat, and cash.

    Just my $.02, correct me if I'm wrong.

    Have Fun!
    -SPNKR
     
  11. Big Elf

    Big Elf Oh no! Not another f----ing elf!

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    3 systems all running a single loop. The only time I might consider dual loops is with multiple high wattage graphics cards AND folding. The system in my sig does OK with a single loop and the CPU temps shown at 4.2GHz increase by only 3ºC if I run Furmark at the same time as P95.
     
  12. Big Elf

    Big Elf Oh no! Not another f----ing elf!

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    From my point of view the advantage of over-radding means that I can upgrade components in my system (to a degree) without having to consider finding space for additional rads. Also because my case would easily take a quad rad. I added the dual rad out of interest as I already had it but it makes a minimal difference to overall temps (at the moment).
     
  13. Guest-44432

    Guest-44432 Guest

    Well after having the CPU/GPU/Motherboard watercooled on 1 loop with a couple of rads, I could notice the water heating up quite quickly. This is why I have gone with 3 loops.
    The benefits for having separate loops for each component;
    1, Cooler temps
    2, Easier to change components for upgrading without having to bleed the other rads and blocks in the system.

    Click on MY RIG in my signature to see how I setup 3 loops.

    Simon.
     
  14. SlowMotionSuicide

    SlowMotionSuicide Come Hell or High Water

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    You just might, but then you would need fans with some serious rpm. Which equals lots of noise. When you have lots of radiator estate you can use sub-1000rpm fans, which in turn results in a very quiet system.
     
  15. Guest-44432

    Guest-44432 Guest

    Running multiple blocks/Rads will restrict the flow of the water. So you will need a fast pump to keep things cool. That's another reason to use separate loops.

    I have my CPU running a 1200LPH pump with a 360mm Rad.
    800LPH Pump for my GPU with a 240mm Rad
    750LPH pump for my Motherboard waterblocks with a 240mm Rad.
     
  16. Burnout21

    Burnout21 Mmmm biscuits

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    single loop, easier to maintain to be honest.

    Both my machines use a single loop, hopefully next upgrade i shall get my paws on a D5 and better 120.3 rad. At the moment my big loop uses just a MCP350 or MCP355 i can't remember and a XSPC RS120.3 i think. Budget rad basically.
     
  17. Big Elf

    Big Elf Oh no! Not another f----ing elf!

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    I have difficulty estimating the amount of restriction that blocks have. I've read various tests that indicate a flow rate of 1gpm is sufficient and that 1.5gpm is optimal. Anything over that reduces water temperatures by 1/10ths of a degree. Those tests are based on US Gallons which are slightly less than Imperial Gallons.

    Using the figures from true_gamer 's examples of pump flow rates gives 4.3gpm, 2.9gpm and 2.7gpm respectively. So that indicates that the components in his loop have a lot of restriction if all together they reduce the flow rate to under around 1.5gpm. So how do you estimate the effect of the different blocks flow rates?
     
  18. Guest-44432

    Guest-44432 Guest

    How is it any easier to maintain? I have not touched my 3 loops since the install a couple of months ago.



    The only real way to test the restriction of a block/rad is to have a flow meter after each component. So by measuring the Pump speed (1200LPH est) from the outlet to the Cpu outlet (800LPH est) to the GPU outlet (400LPH est) to a Rad outlet (300LPH est) to the reservior. (The LPH are guess work to give an example).
     
    Last edited by a moderator: 18 Aug 2010
  19. Combatus

    Combatus Bit-tech Modding + hardware reviews Lover of bit-tech Super Moderator

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    This is a very subjective issue in that we all want different things from our setups. For me, noise reduction is important so I tend to have all the fans on my rads at or below 1000rpm. For others noise if less of an issue.

    Skinneelabs has data on how much heat rads can dissipate - typically a full size 3 x 120mm rad with 1000rpm fans copes fairly well with a 300W heat load (about the same as a stock speed I7-920 and an HD 5850 would produce in a relatively demanding game).

    If you're PC is producing more heat than that (it almost certainly will if your CPU is overclocked) then you're either going to have to increase the fan speed or get another radiator to see real benefits from water cooling. Yes a 2 x 120mm rad will cope but your temps will be much higher or you'll be using much noisier fans which to me half defeats the point of water cooling in the first place.

    Certainly from my own systems and the ones we've built at bit-tech, you're looking at a 3 x 120mm rad to cope properly with an overclocked Core i7 without things being louder than a decent air cooler. I have an overclocked Core i7, GTX 280 and a full cover block for my board with 3 x 120 and 4 x 120mm rads in the loop and they cope well. If I turn the fans on the 4 x 120mm rad off, the 3 x 120mm gets very hot very quickly.
     
  20. SPNKR

    SPNKR Pretty Good Kid

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    This makes sense to me, but one thing I have yet to find anywhere online is an explanation of heat wattage. Since you understand it, how does it translate, or does it translate at all, to power consumption wattage, and how I determine the heat wattage for my system. Is there like a comprehensive guide anywhere that you know of? (yes I have googled it many times:D)

    Anyways, thanks for the insight.

    -SPNKR
     

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