Upgrade Watercooling : Dual or Single loop ?

[SherNan]

Hello allz !

First of all, I hope you'll understand me well beacause I'm french and my english is not so good

I would like to improve my actual watercooling loop.
So I decided to dismount all my computer to clean it the best that I can, specialy my watercooling loop (with Mayhem Blitz Part 1 for waterblocks and Part 2 for rads) before changes...

Here is my question : on a same tank double 5,25" tank from Alphacool), do you thing dual loop could be a good idea ?

Here is what I'm thinking about :
Loop 1 : Tank -> CPU (i7-3990K) -> Rad Alphacool XT45 280mm -> Tank
Loop 2 : Tank -> Rad EK 240mm ep25 -> GPU (GTX 1080Ti) -> Rad Phobya Monsta140mm -> Tank

Thanks in advance for your anwser,

Best regards,

S

 

[Chris Beard]

Yes, I think this is a good idea; I imagine by sharing a tank (reservoir) you increase the volume of water for both loops (more readily absorbing either CPU or GPU heat spikes) whilst keeping the benefits of a high flow rate that dual loops presents.

I see no disadvantage in theory, although I've not seen this before in practice.

 

[SherNan]

Yes, I think this is a good idea; I imagine by sharing a tank (reservoir) you increase the volume of water for both loops (more readily absorbing either CPU or GPU heat spikes) whilst keeping the benefits of a high flow rate that dual loops presents.

That's exactly what I'm thinking about... I can't increase the size of the radiators because of my PC case.

I see no disadvantage in theory, although I've not seen this before in practice.

I'll tell you if it's better

Thanks anyway for your answer !

 

[3t3P]

generally doing something at a larger scale is inherently more efficient.

Single loops have less maintenance and less points of failure also. Look cool though

 

[Toothy1911]

Yes, I think this is a good idea; I imagine by sharing a tank (reservoir) you increase the volume of water for both loops (more readily absorbing either CPU or GPU heat spikes) whilst keeping the benefits of a high flow rate that dual loops presents.

I see no disadvantage in theory, although I've not seen this before in practice.

Once up to temperature there's not going to be much benefit of more water in the loop.
Unless OP wants the look of dual loop, just stay single. The extra cost and hassle is not worth it.

 

[Avathar77]

Are you using 2 tanks or the same?

 

[SherNan]

Are you using 2 tanks or the same?

One tank, a dual 5,25" bay from Alphacool

 

[Chris Beard]

Once up to temperature there's not going to be much benefit of more water in the loop.
Unless OP wants the look of dual loop, just stay single. The extra cost and hassle is not worth it.

I understand that in real world use heat soak can be quite useful. Besides, here we are really talking about a single loop with parallel pumps, since there is a common res.

 

[LuckyBenski]

Parallel pumps, blocks and radiators I presume?

Something to consider is that D5 pumps dump heat into the the loop. Two pumps doubles this amount, even if it's small.

 

[SherNan]

Parallel pumps, blocks and radiators I presume?

Something to consider is that D5 pumps dump heat into the the loop. Two pumps doubles this amount, even if it's small.

Parallel pumps, blocks and rads yes.
Pumps are Laing DDC-1T+, don't know if they heat as much as D5

 

[LuckyBenski]

Parallel pumps, blocks and rads yes.
Pumps are Laing DDC-1T+, don't know if they heat as much as D5

No, they eject heat externally. It's one of the reasons they can be smaller, and why they tend to have a heatsink on the back. Tradeoffs, less heat in the water, much smaller pump, but a small amount of heat in the case

 

[SherNan]

No, they eject heat externally. It's one of the reasons they can be smaller, and why they tend to have a heatsink on the back. Tradeoffs, less heat in the water, much smaller pump, but a small amount of heat in the case

Thank you about this info !

About heat in the case, I would love to have your advice all...
Here is what I'm going to set up with fan and rads :

TOP : rad 280*45 - fan push - out of case
BACK : rad 140*60 - fan push-pull - out of case
FRONT : rad 240*25 - fan push - in the case

All fans are Noctua IndustrialPPC PWM, controlled by a NZXT Grid+CAM.

Here is the questions :

Does the air flux seem ok to you guys ?
What happen if I putt all fans in extracting mode (I mean out of the case) without a fan to provide some fresh air inside the case ?
On the Push-Pull Rad, do the fans have to get the same speed ? Will it be better to speed up a little bit more the pull fan to avoid air stagnation into the 140*60 rad ?

thanks for your reply

 

[Bugbait]

Unless you're doing it for looks, stick with a single loop. If you want dual pumps (I do) then run them in series. Pumps in series have the same flow (maybe very slightly increased) but increased pressure (good). Also adds a level of redundancy for both the CPU and GPU being cooled. The disadvantage of a dual loop is that you can't utilise the excesses cooling from the other loop. You GPU will churn out more heat than your CPU for instance. Why not have all 3 radiators available to the CPU and GPU?

 

[SherNan]

Unless you're doing it for looks, stick with a single loop. If you want dual pumps (I do) then run them in series. Pumps in series have the same flow (maybe very slightly increased) but increased pressure (good). Also adds a level of redundancy for both the CPU and GPU being cooled. The disadvantage of a dual loop is that you can't utilise the excesses cooling from the other loop. You GPU will churn out more heat than your CPU for instance. Why not have all 3 radiators available to the CPU and GPU?

Thanks for your answer and advice bro, because of your explanation, I understand the disadvantage of a dual loop, but is it still the case if both loops are on the same tank ?
I thought the excesses cooling from the CPU loop would be used by the GPU's one in the tank...

My thought is increase the flow on both waterblocks creating a dual loop on a same tank, shorter than one with CPU+GPU on a same tank

 

[Bubo]

On the Push-Pull Rad, do the fans have to get the same speed ? Will it be better to speed up a little bit more the pull fan to avoid air stagnation into the 140*60 rad ?

There should be no harm in running the push or pull fan at a slightly higher speed, as the pull fan will simply accelerate whatever air is being fed into it from the other fan, but it is fairly traditional to just daisy chain the fans so they run off one fan header, and I doubt trying to offset the speeds will give any meaningful performance benefit in practice. Also, a potential issue with fans in close physical proximity and running at slightly different speeds is that you can get beat vibration, as their vibration goes in and out of phase. Basically it will sound like a slow rise and fall in vibration noise, depending on how far apart the speeds are. This can actually end up being more annoying than the base vibration noise.

I started my water cooling career with a duel loop setup, but eventually came around the the single loop idea mainly because it makes for a vastly easier loop, with less tubing, and the performance difference is negligible.

 

[Bugbait]

Thanks for your answer and advice bro, because of your explanation, I understand the disadvantage of a dual loop, but is it still the case if both loops are on the same tank ?
I thought the excesses cooling from the CPU loop would be used by the GPU's one in the tank...

My thought is increase the flow on both waterblocks creating a dual loop on a same tank, shorter than one with CPU+GPU on a same tank

You could have different temperatures of water equalising in the tank but I don't envisage any advantage over a single loop. The advantages of a higher flow plateau at around 1 US gallon per minute or 3.8 litres. It's been tested that increased pressure also aids cooling. If your flow is sufficient, which a single D5 or DDC (18w version) can handle for most "normal" loops then you're not getting any cooling advantage by increasing the flow via dual loops. A pressure increase would ensure that the CPU and GPU in a single loop is maintaining a higher flow.

I have a long loop in a super tower case that goes through a 480 (top), 360 (front) and another 480 (bottom). The loop length is extended due to routing (hiding parts of looks) but my dual D5's at full speed will still cause the water in the reservoir to churn with an anti-cyclone fitted. The flow is more than adequate with the bonus of redundancy. One pump could easily keep the cooling going, I've tried by switching one of them off via the Aquaero.

 

[SherNan]

There should be no harm in running the push or pull fan at a slightly higher speed, as the pull fan will simply accelerate whatever air is being fed into it from the other fan, but it is fairly traditional to just daisy chain the fans so they run off one fan header, and I doubt trying to offset the speeds will give any meaningful performance benefit in practice. Also, a potential issue with fans in close physical proximity and running at slightly different speeds is that you can get beat vibration, as their vibration goes in and out of phase. Basically it will sound like a slow rise and fall in vibration noise, depending on how far apart the speeds are. This can actually end up being more annoying than the base vibration noise.

Understood, and thanks for the advice
I use NZXT Grid + CAM to control my fans, it is provided with 2 splitters so I can plugg on one of those the push/pull fans

I started my water cooling career with a duel loop setup, but eventually came around the the single loop idea mainly because it makes for a vastly easier loop, with less tubing, and the performance difference is negligible.

I understand but I did some mesurements in my PC case and surprisingly, dual loop on a same tank allow me to use less tube than a single loop

 

[Bugbait]

I understand but I did some mesurements in my PC case and surprisingly, dual loop on a same tank allow me to use less tube than a single loop

Do they use the same number of 45 and 90 degree bends? This will have a greater impact on flow than more straight tube unless it's much longer and all going vertical.

 

[Bubo]

Another thing I have done with my most recent build was to have one rad on PCM style fans running off a mobo header, and one with normal fans on a fan controller. This is with a 360 and a 240 rad. With it all in one loop, I have the mobo bios set to ramp up the fans on the 360 rad as the cpu temp goes up, and the other rand set to run at a manual speed through the controller. This way I have a base level of cooling on the 240 rad which is there all the time, and automatic extra cooling on the other when needed. This helps keep the noise down during non gaming use. This is something which you could do with a duel loop as well of course if you used the mobo headers for some fans, or if that controller gizmo you have allows for temperature measurement and feedback control, but I get the feeling having it all in one loop would make it easier to have one rad act as the one to "kick in", when needed, whenever the CPU or GPU, or both start to dump heat into the loop.

Edit: Actually with your three rads, you could set them them up to cascade as more cooling is required, if they were all in one loop. Sounds like that controller would let you do this. Maybe have the one which would be on permanently at full speed as the intake to the case.

 

[SherNan]

Actually with your three rads, you could set them them up to cascade as more cooling is required, if they were all in one loop. Sounds like that controller would let you do this. Maybe have the one which would be on permanently at full speed as the intake to the case.

Thanks for this advice