Waterflow in multiple GPU block in serial or parallel

[steveroch-rs]

Hi guys,

 

this is a newbish question but I just can't get it down. Does it matter which direction the water flows inside a GPU block? I mean if I have 2 cards, and I enter the 1st on the bottom left, exit it on the bottim right and go up to the top right in/outlet of the 2nd GPU, the water is flowing backwards am I right? Do I have to make a 45° turn to get from bottom right to top left so that the water flows the same direction in both blocks or doesn't it matter?

 

Thanks

 

Steve

[Moonzy]

i nvr watercooled but the direction of flow in a block doesnt matter, as long as there are flow,

there's no valve in the blocks

 

also, series or parallel would pretty much be the same

[my guess]

series (liquid flow from block 1 to block 2): block 1 is slightly cooler than block 2, but not much difference

parallel (liquid flows same rate in both blocks at same time): both blocks run slightly hotter together (assuming same flow rate as above)

[/my guess]

 

but some say that series is fine because the water temperature stabilises, but i dont think this is how fluid dynamics work

[KE2012]

If you have ever seen Jayztwocents skunkwork build on youtube you will notice that his cards are in parrallel and he has commented on it before to say it makes no differece as to if they are in parralell or series. So go for parralell if you want it in that set up.

 

Also some blocks do have optimal directions but I've only seen that on CPU water blocks, not GPU blocks, but check your manual to your block if you are unsure.   

[jasonvp]

40 minutes ago, steveroch-rs said:

I mean if I have 2 cards, and I enter the 1st on the bottom left, exit it on the bottim right and go up to the top right in/outlet of the 2nd GPU, the water is flowing backwards am I right?

There's no concern with which input and output you use.  You could go straight in, out, in, and out on the same hole(s) on the 2 GPUs.  After a short period of time, the blocks would fill with liquid, and flow.  But it's not ideal.

 

The best thing to do is exactly what you've posted.  It also makes no difference re: the flow direction of the fluid.  If we assume the inlet/outlet holes are numbered 1-4 (2 on one side, 2 on the other), then ideally:

• In GPU1 hole 1
• Out GPU1 hole 4
• In GPU2 hole 2
• Out GPU2 hole 3

And you're good.

[TidaLWaveZ]

https://linustechtips.com/main/topic/527286-parallel-flow-between-two-video-cards/

[steveroch-rs]

3 minutes ago, TidaLWaveZ said:

https://linustechtips.com/main/topic/527286-parallel-flow-between-two-video-cards/

Now it all makes sense! Thanks bro  now I get at least the parallel part  But I think since flow direction doesn't matter (obviously J2C is also going in at the "outlet" first) I can ignore the serial one.

[xgn]

Im a fan of serial. I dont know if it make a difference. But in case of serial all the water gets changed everytime.

[jasonvp]

A bit to absorb here, but the text is worth reading and the diagrams clear everything up.

 

http://koolance.com/help-video-block-connecting

 

 

[Dango]

I always prefer Parallel over Serial. Parallel will lower the restriction in the loop overall. If the pump is at the same speed, parallel will have higher flow rate than serial, which means better temp. The temperature different between this two set is depend on what kind block are you using.

 

My personal rig's block have really low restriction, so I can turn the pump down a lot without lose much performance(like fan on the radiators).

[Necrodead]

4 hours ago, Dango said:

I always prefer Parallel over Serial. Parallel will lower the restriction in the loop overall. If the pump is at the same speed, parallel will have higher flow rate than serial, which means better temp. The temperature different between this two set is depend on what kind block are you using.

 

My personal rig's block have really low restriction, so I can turn the pump down a lot without lose much performance(like fan on the radiators).

This is true, however its good to also note that each consecutive parallel block will lower the overall flow as well as the restriction. This just means if you have a really weak pump you don't always want to go for 3 or more blocks in parallel, as when you get to lower than ~1gpm flow rate your temps will go up. Each extra block added to a parallel setup halves the flow rate. D5's and DDC's are strong and can probably keep 1+ gpm on even low settings so this is just to note if you happen to have a lesser pump.

[TidaLWaveZ]

15 hours ago, steveroch-rs said:

Now it all makes sense! Thanks bro  now I get at least the parallel part  But I think since flow direction doesn't matter (obviously J2C is also going in at the "outlet" first) I can ignore the serial one.

 

Yeah, as soon as I saw this thread I remembered when I was in the same boat.  The part I couldn't seem to grasp was that the flow doesn't have to take one single set path, it can split paths in a multi-gpu loop.