Overclock.net › Forums › Cooling › Water Cooling › Two Loops or One?
New Posts  All Forums:Forum Nav:

Two Loops or One?

post #1 of 9
Thread Starter 
The components are a D-tek Fuzion and a D-tek GFX. There is also a Viper John northbridge block, but its contribution is small and will be modeled as a MCW-30.

Using the rads in Martin's spreadsheet the analysis will use Thermochill PA120.3s

One loop:
Fuzion→GFX→NB→XSPC-topped DDC3.2→XSPC-topped DDC3.2→PA120.3→PA120.3
Pressure 10.52psi, flow 1.39gpm, velocity out of nozzle 18.9fps

Two Loops:
Fuzion→XSPC-topped DDC3.2→PA120.3
Pressure 5.40psi, flow 1.19gpm, velocity out of nozzle 16.2fps

GFX→NB→XSPC-topped DDC3.2→PA120.3
Pressure 5.06psi, flow 1.63psi

In the one loop scenario, the CPU may see reduced water temps in addition to increased flow.

In the two loop scenario, the GPU may see reduced water temps in addition to increased flow.

Which is the the better scenario?
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
post #2 of 9
Loop One, As GFX Cards can withstand greater temps, but i personally would have two loops, one loop for cpu and one loop for your video card.
post #3 of 9
Two loops would look cooler

No pun intended.
Xplor
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q9450 @ 3.4Ghz (425 x 8) DFI DK P45-T2RS PLUS Palit 9800GT 2GB Corsair XMS2 DDR2-800 @ 850 5-5-5-15 
Hard DriveOptical DriveOSMonitor
WD 500GB SataII LG HD DVD, Blu-ray Combo Drive Windows Vista Ultimate Samsung 226BW 
KeyboardPowerCaseMouse
Logitech Wireless 550w Generic Lian Li PC-A70B (Soon to be modded) Logitech Wireless 
Mouse Pad
Desk :D 
  hide details  
Reply
Xplor
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q9450 @ 3.4Ghz (425 x 8) DFI DK P45-T2RS PLUS Palit 9800GT 2GB Corsair XMS2 DDR2-800 @ 850 5-5-5-15 
Hard DriveOptical DriveOSMonitor
WD 500GB SataII LG HD DVD, Blu-ray Combo Drive Windows Vista Ultimate Samsung 226BW 
KeyboardPowerCaseMouse
Logitech Wireless 550w Generic Lian Li PC-A70B (Soon to be modded) Logitech Wireless 
Mouse Pad
Desk :D 
  hide details  
Reply
post #4 of 9
I'm basing my answer on Martin's "Sections" rule of thumb:

http://www.overclock.net/water-cooli...d-my-rads.html
Sort of a rule of thumb might be around 180 watts per 120mm section of radiator using high speed fans and assuming a 10C delta.But I wouldn't be happy with a 10C delta, so I'd cut that down in half. so about 100 watts per section.

CPU would be 1.5 sections, GPU 1.5 sections, NB .5 sections or 3.5 sections.


In the single loop scenario, the total section requirement is 3.5. With two PA120.3s, you have 6 sections. The ratio of available sections to needed sections is 1.7 (6/3.5 = 1.7).

In the dual loop scenario, each loop has 3 rad sections available. The CPU loop requires 1.5 sections, so it's available/needed ratio is 2. In the GPU/NB loop the requirement for is for 2 sections, so it's ratio is 1.5.

If you define "Better" as meaning total cooling capacity available, then I would say the dual loop wins, and it provides more cooling capacity to the cpu - the most heat sensitive component (2 vs 1.7). In reality, both the single loop and the dual loop provide more than the required cooling capacity, so do whichever is most desired/convenient.

A different way to look at it, though is which scenario gives you the most remaining idle capacity (rad sections available minus rad sections required). In the single loop you have 2.5 sections available (6 - 3.5). In the dual loop scenario, the CPU loop has 1.5 sections available (3 - 1.5) while the GPU/NB loop has 1 section available (3 - 2). In the single loop, you could add another GPU for SLI and still have idle section capacity. In the dual loop, you would have to add the GPU to the CPU loop, and would then be at max capacity on that loop. Adding it to the GPU/NB loop would exceed capacity. Looking at it this way, the single loop might provide a better option as it gives more total idle capacity (for adding future components).

OF course if you disagree with this rule of thumb, then you may disagree with my answer.

post #5 of 9
Thread Starter 
The CPU probably generates twice the heat of the GPU. In the dual loop scenario it has a lower flow rate, less pressure, and probably cooler water.

However, that comes at the expense of the GPU. However, the difference to the GPU is small.

In reality, the single loop would probably be a GTX480 with two-stage 8 fan setup, the dual loop would probably be a GTX360 and a BIX360. However, Martin doesn't have data for those.
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
post #6 of 9
To be honest, I just played along. I think we tend to over analyze things that don't require that much analysis. With so many other variables, and differences being only a couple of degrees one way or another, Martin's Rule of Thumb is probably about as detailed as you need - maybe add up watts generated and subract from rads watts capacity - but that doesn't account for different fans, block seating, TIM efficiency, loop restrictions (bends and kinks), coolant efficiency, tubing lengths, and on and on.

My suggestion - try it both ways and see which one you feel is "best."
post #7 of 9
Thread Starter 
It may or may not be a few degrees though. The question is when do those few degrees mean the difference between a successful and unsuccessful overclock?

My computer was switched to water because an inablity in keeping temps under mid 60s on a quad. Then I found water dramatically improved temperature stability in addition to handling higher temps.

I tend to believe that a single loop is better. Certainly less complicated. I also think that the current shoot a get of water at a wall philosphy of water block design favors the higher pressure and flow rates. The limiting factor may be when the pressures or flow rates are two high for other components creating leaks and cavitation respectively. We don't seem to be there though.

Working on my race car I was forced to get involved in cooling system design. Ended up with drain tubes in the back cylinder head, a bleed at the highest point in the engine, a swirl tank (I guess similar to our reserviors, however adding a de-aeration feature, better pump design (more flow/pressure at higher efficency..1-2 hp means alot when you only have 450. The duct work was critical, and the car uses different radiators on hot and cool days.

A note on the hp...whether a pass is successful is measured in inches...did you get along side the door or just ahead of the rear tire? A couple of hp may be all that is needed to make the difference.
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
post #8 of 9
If you have all of the components in the OP, then you can try it both ways and there's no longer a need to "believe" or "think".
post #9 of 9
Thread Starter 
Virtually no one here has adequate testing equipment to do that. And we all make significant compromises--using DDC3.2 or D5 pumps, etc.--similar to hot rodders using small-block Chevys

In many ways what we are doing is like a hot rodder modifying a a 32 Ford. The big tires and the supercharger sticking out of the bodywork say powerful race car. The paint and upholstery say show car.

Here our radiators, water blocks and pumps say extreme overclockers. Windowed cases, fancy paint, LEDs and UV say more show than go. The difference between a hot rod from the late Boyd Conddington and NASCAR's Hendrick racing, which is rumored to employ over 50 PhD engineers.
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
Number 1
(13 items)
 
  
CPUMotherboardGraphicsRAM
Q6600 B3 EVGA 780i A1 MSI GTX260/192 2x2GB Corsair Dominator PC1066 
Hard DriveOptical DriveOSMonitor
1x500GB Maxtor 1 Asus SATA Vista x64 Ultimate 32" 1080P TV 
KeyboardPowerCaseMouse
Logitech Wave USB 1000w Cooler Master Lian Li V2000 Ideazon Reaper Edge 
Mouse Pad
QPad QT-R 
  hide details  
Reply
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Water Cooling
Overclock.net › Forums › Cooling › Water Cooling › Two Loops or One?