Separate loop or single loop question.

[suits]

So right now I've got a 360mm rad and a 240mm rad for both GPU and CPU. I have the ability (spare parts) to separate the loop and do one for a GPU and one for the CPU. 

 

Would it it be more beneficial to run separate loop even though I'm only running a 360mm on the CPU and a 240 on the GPU. Or is it more beneficial to have them both in the same loop?

[VioDuskar]

seperate loops are pointless, i won't go into the thermo-physics of it, but a single loop is better. many pros, no cons compared to separate loops.

[DocSwag]

Unless your temps are really high I don't see why you would need to.

[VioDuskar]

2 minutes ago, DocSwag said:

Unless your temps are really high I don't see why you would need to.

even then, you won't see a difference. if you are water cooled the only thing that can reduce your temps is more water capacity, more radiators, or better fans (up to the maximum dissipation point of the radiator metal.)

[DocSwag]

Just now, VioDuskar said:

even then, you won't see a difference. if you are water cooled the only thing that can reduce your temps is more water capacity, more radiators, or better fans (up to the maximum dissipation point of the radiator metal.)

Two loops would increase water capacity while requiring two pumps, increasing water flow, both of which should decrease temps.

[VioDuskar]

Just now, DocSwag said:

Two loops would increase water capacity while requiring two pumps, increasing water flow, both of which should decrease temps.

not true, two loops is not the same as increasing water capacity, it's the water capacity of the entire single loop that must increase. additionally, increasing water slow will not decrease temperatures. 

 

I really, don't want to go on a long rant about the thermal dynamics of it, please don't make me.

 

[DocSwag]

2 minutes ago, VioDuskar said:

not true, two loops is not the same as increasing water capacity, it's the water capacity of the entire single loop that must increase. additionally, increasing water slow will not decrease temperatures. 

 

I really, don't want to go on a long rant about the thermal dynamics of it, please don't make me.

 

You're gonna need two reservoirs though, which should generally increase water capacity. Of course, it's not guaranteed to but it should. 

 

As for water speed, actually yes it will. It's a similar concept to wind chill.

Also, I'm pretty sure you're not supposed to say thermal dynamics but thermodynamics  

[VioDuskar]

@DocSwag you didn't listen to what he said at 7:00+ did you? 

 

he's basically cutting the flow to almost nothing. listen to what he said at 8:45ish. YOU WONT SEE MUCH OF A DIFFERENCE BETWEEN MAX AND MIN.  

 

that's because once all of the water is heated in the loop the best you can do is dissipate it better via more radiators, or adding more water to absorb more heat. take some lessons on heat capacity and specific heat. 

 

it's not like windchill, it's like blood. blood at any point in your body is the same temperature. even if you have high or low blood pressure. 

after the loop has ran for a short while the entire loop with have a very small delta at any given point in the loop, there becomes no such thing as pushing GPU heat into a CPU. thus it is unnecessary to have two loops in one system.  Jay has another video explaining this, but it's 30+ minutes long and from like 2012.  

 

a system can benefit from two pumps in series, in terms of noise and redundancy, but once you get your liquid to full heat capacity, your flow rate is nearly negligible, as long as it's flowing properly. the flow vs dissipation curve looks like a root function graph, diminishing returns until no return. 

 

@suits there is no need to make two loops, you will not pump heat into one component to another, so don't worry. two reservoirs or two pumps can be beneficial in series, but not needed.

[DocSwag]

1 minute ago, VioDuskar said:

@DocSwag you didn't listen to what he said at 7:00+ did you? 

 

he's basically cutting the flow to almost nothing. listen to what he said at 8:45ish. YOU WONT SEE MUCH OF A DIFFERENCE BETWEEN MAX AND MIN.  

 

that's because once all of the water is heated in the loop the best you can do is dissipate it better via more radiators, or adding more water to absorb more heat. take some lessons on heat capacity and specific heat. 

 

after the loop has ran for a short while the entire loop with have a very small delta at any given point in the loop, there becomes no such thing as pushing GPU heat into a CPU. thus it is unnecessary to have two loops in one system.  Jay has another video explaining this, but it's 30+ minutes long and from like 2012.  

 

a system can benefit from two pumps in series, in terms of noise and redundancy, but once you get your liquid to full heat capacity, your flow rate is nearly negligible, as long as it's flowing properly. the flow vs dissipation curve looks like a root function graph, diminishing returns until no return. 

 

@suits there is no need to make two loops, you will not pump heat into one component to another, so don't worry. two reservoirs or two pumps can be beneficial in series, but not needed.

I'm too lazy to watch it again

 

Also, there is a difference, it's just not very big, due to water being a pretty good thermal conductor, but there is some. There's a reason why he got lower temps.

 

I never said it was a big difference, I just said that there IS a difference

 

2 loops isn't and won't ever really be worth it for thermal reasons, only for aesthetics.

[For Science!]

1 hour ago, DocSwag said:

Two loops would increase water capacity while requiring two pumps, increasing water flow, both of which should decrease temps.

 

1 hour ago, VioDuskar said:

even then, you won't see a difference. if you are water cooled the only thing that can reduce your temps is more water capacity, more radiators, or better fans (up to the maximum dissipation point of the radiator metal.)

 

1 hour ago, DocSwag said:

You're gonna need two reservoirs though, which should generally increase water capacity. Of course, it's not guaranteed to but it should. 

 

As for water speed, actually yes it will. It's a similar concept to wind chill.

Also, I'm pretty sure you're not supposed to say thermal dynamics but thermodynamics  

I would have to agree with VioDuskar in this case. More radiators in a single loop will be a better choice.

 

under most situations your cpus and gpus will not be under full load at the same time so having a 240+360 rad cooling the single component under load will allow for better heat dissipation. This also holds true even if both components are under full load.

 

Although the posters above mentioned total water capacity improving cooling performance, I would say this is slightly inaccurate. having a larger body of water would mean it would take longer for the system water to reach equilibrium (and thus stay closer to ambient temperature for longer) however the final cooling capacity is dictated by the radiator area and fan speed and so the system would ultimately reach the same temperature over time even if you had a bigger reservoir.

 

so in summary single loop is better. the one advantage of a dual loop is if you know you want to swap out gpus or cpus often and so you can drain one part of the loop without affecting the other.

[Mick Naughty]

Do which ever. Wont matter with such few components and radiators. If you have the room and want to do that much work go right ahead.

 

I have a single pump for 2 rads and 8 blocks.

I also ran 5 rads for 3 blocks and 1 pump.

 

I will only do a dual loop for a large case like my x9, just to take up more space and to swap out cards easier.

[DocSwag]

4 hours ago, For Science! said:

 

 

I would have to agree with VioDuskar in this case. More radiators in a single loop will be a better choice.

 

under most situations your cpus and gpus will not be under full load at the same time so having a 240+360 rad cooling the single component under load will allow for better heat dissipation. This also holds true even if both components are under full load.

 

Although the posters above mentioned total water capacity improving cooling performance, I would say this is slightly inaccurate. having a larger body of water would mean it would take longer for the system water to reach equilibrium (and thus stay closer to ambient temperature for longer) however the final cooling capacity is dictated by the radiator area and fan speed and so the system would ultimately reach the same temperature over time even if you had a bigger reservoir.

 

so in summary single loop is better. the one advantage of a dual loop is if you know you want to swap out gpus or cpus often and so you can drain one part of the loop without affecting the other.

I'm not disagreeing with that . I'm just saying that having two loops DOES give a slight performance advantage, it's just EXTREMELY slight.

[Drak3]

The only benefit of dual loops is easier troubleshooting. Since your GPU(s) are on a separate loop than your CPU, it will be easier to find clogged blocks, especially if you only have 1 GPU.

Otherwise, it's all about aesthetics.

[0ld_Chicken]

I've played around with dual loops a couple times and imo it isn't worth it unless you're running 3x Titan X  and a 6950x or something like that.  What I found was that when gaming, my GPU loop with 2x gtx 980's would get too hot for my liking, even with a 280mm and a 140mm radiator.  Meanwhile, my cpu loop was ice cold with a 240mm radiator and by separating the loops I was removing the ability to use all the radiators capabilities all the time.  Unless you are perfectly balancing your radiator space then you will likely get less effective cooling by going with 2 separate loops because one portion of the loop (likely the cpu loop) won't be using the radiator to it's full extent, while the other is operating at it's thermal limit.  Especially true while gaming since most games won't utilize most cpu's to 100% so they aren't even dumping that much heat.   The GPU will likely run at/close to 100% the entire time dumping heat into the loop.

 

unless you've got the space to completely overkill both loops with radiators, I would just stick with a single loop.  

[Ithanul]

Like other individuals have stated.

Pointless in a every day computer or gaming computer.  Even a folding/boinc rig can get away with a proper single loop when built right (a good amount of radiators).

 

In the case of your components, it is a waste of money, time, and effort unless you going for looks.

 

To give you an idea, I fold and boinc (these two put greater loads than gaming) on two highly OCed 980Tis and previously a delid 4770K.  Highest temps I saw was 50C on the GPUs and 60-65C on the CPU at full loads on all of them.  This is with a 360 and 200 radiators in my loop.  You have an extra 40mm length radiator to me.  You will be fine.