special dual radiator airflow consideration

[flammen]

Hey there,

 

I am running a single loop in a self-made case. The only Intake is at the bottom and the only exhaust is in the top. Both places are populated with 420mm Radiators, respectively. And that is the problem: The hot air comming from the bottom radiator is getting sucked into the top radiator, which nearly completely eliminates the top radiators cooling capability. When I have 25°C ambient and my water is at 30°C, the air inside the case gets 29.5°C - that means that the top radiator, which is sucking this 29.5°C air, can not cool down the water any more.

I have thougt about that and have an idea now, but I am not positive about:

Would it be helpful to set up 2 dedicated loops:

- One for the CPU (i7 3770k @ stock, max 60W while gaming), which has a much lower heat output, using the bottom radiator. 

- And the second one for the GPU (GTX 1070 @ 2.2GHz, up to 200W), using the top radiator.

 

A configuration like that shoud keep the bottom radiator cool and therefore utilize the top radiators cooling capability, which should result in a cooler system after all.

(temp(CPU) + temp(GPU) should be lower then now)

 

Is that a good idea? It is my first loop and I have really no experience  so any thougts are highly appreciated!

 

BTW, the case features a 90° inverted layout, which results in a very nice bottom-to-top airflow. Because of that, adding Fans in the front or back is no option - I think 6 fans is enough anyway  

 

thanks in advance!

 

flammen

[For Science!]

2 hours ago, flammen said:

-

 

Long story short: bad idea. One single loop will almost always outperform dual loops.

 

Idle temperatures should not be a concern when you think about the temperatures. Its when the water is getting 40-55 degrees when the radiators start to shine. Your components are very low heat generating anyway so it's going to be a none factor with 820mm radiator space.

 

The flip side of the coin however is that you have so much radiator space for just 2 components so it legit won't matter how you do it.

[flammen]

Thanks for the reply!

 

Water temps are not a concern, I rarely get a 10 Kelvin Delta under full system load. It is just academic, for optimizing it as much as possible. Also I want to upgrade to a 6-core in the near future.

 

It makes a lot of sense that a single loop distributes the heat more and outperformes dual loop configurations.

Hypothetically, if I would build a dual loop system anyway: How hot would the CPU loop get? (The CPU is again a i7 3770k @ stock) The radiator is a low fin density 36mm thick (XSPC EX420) with 3 Noctua NF-A14 at fix 500 rpm. It is not a high-performance 420 rad, but still a 420 rad. Maybe someone could give me a good guess?

 

Thanks a lot!

 

flammen

[For Science!]

6 minutes ago, flammen said:

-

"not very hot" is as far as I'm going to say. Only somebody who has the exact same setup will be able to give you an answer on this one.

[Tam3n]

If you want to improve your CPU temps with a minor degradation to your GPU temps, doing what you described should work.

If you don't use a side panel, you will solve your problems and increase the overall performance by changing top to in take also.

[flammen]

Thank you for your thoughts!

Does changing the GPU temperature from about 45°C under load to say 50°C or 55°C impact the GPU overclock? I heard that Pascal GPUs start dynamically dropping frequency only when they hit 60°C - is that true?

I really dont want to loose my side panel, because of the dismantled PSU inside, but thanks for the idea!

 

flammen

[Mick Naughty]

I’d rather go single loop. But when I game th cpu is either maxed out or above 50/60%. Plenty of heat regardless. 

 

As as far as gpu clock, it starts dropping at 39/40c. Which shouldnt be an issue with the amount of space you have. 

[flammen]

Thanks for your reply!

 

I am wondering if anyone has ever build a dual loop, which can be transformed into a single loop if needed and vice versa. You just open the valves to get a single loop-like configuration, where water is exchanged between the loops and every component can use the total radiator space. Or you close the valves and seperate the loops from each other. I made a schematic sketch below.

Is there any major downside to this "customizable" solution? I could not find anything obout.

 

flammen

[Mick Naughty]

That would be a dual loop no matter how you look at it. 

Work wouldn't be worth the benefits, not like there are any to be had.