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Radiator sizing, silence and dissipation

6K views 12 replies 6 participants last post by  Cooked CPU 
#1 ·
I need advice on radiator size. What I'd like to achieve is as silent as possible, while maintaining high performance - thus I expect high rad surface as a main requirements, but not sure if there are diminishing returns at any point. Running 5960X@4.5+ (1.35V), dual Titan Xp @ 2.05+ with dual M2 SSDs also cooled.

How far should I go? 2x 360 enough? 2x 480? 2x 560? Dual loop or single serial?
 
#2 ·
You need to determine how many watts of heat you need to remove first. Don't forget overclocking if you're going to be doing that. Then choose the fans you want to use. You'll need to choose a pump and blocks and get an idea of what tubing and fittings you will be using.

With the flow rate of the pump you can calculate the flow rate you'll get through the restriction of the blocks, tubing and fittings. Then you can start looking a rads the will remove the amount of heat you need removed with that flow rate and the fans you'll use. Don't forget to also add in the flow restriction of any rad you're looking at too.
 
#3 ·
With your overclock on the cpu and 2xgpu, it's about 1000w according to the evga psu calculator. Add 10-20w for pump... and ssd heat load is hard to calculate with the calculator. So, we will call it 1050w load.

What water delta are you looking at staying around? For a relatively quiet build at 10c water delta, you're looking at roughly 100w/120mm^2 surface area with 1000-1100rpm fans. So, at your overclock, you would need about 10x120^2 surface area calculating only the radiators releasing heat. Heat is released through tree blocks, tubing and fittings as well inside the case, but considerably less than radiators. We can estimate that 80% of heat will release through the radiators. So, designing the radiator surface area for about 850w would mean that roughly 8 or 9x 120^2 would give you the cooling you are looking for.

You could use 2x480 if silence wasn't really a priority or didn't mind slightly higher water delta at full loads, but 2x360 will be a little low for your heat load and search of silence.

I personally design my systems to have as much surface area as I can... I usually don't reduce the amount of heat that the blocks/tubing/fittings release, and look to exceed the wattage at load with radiator dissipation wattage.

What case are you planning to use? If you can fit more than 2x480, I would. Also, if your case can use 140mm wide radiators, you would be able to increase surface area if you cannot go with a longer radiator.

I personally prefer single serial loops, gpus in parallel, but in series on the loop. With separate loops you always lose out on potential cooling performance from radiators with less load. With a separate loop, you may need something like 2x360 for the gpus and a 360 for the cpu.

As far as pumping power, you could run off one good D5 or DDC pump so long as your blocks and radiators are not very restrictive. You can do the math, but in general, gpu in parallel reduce restriction and most cpu blocks are much less restrictive than what trey used to be. Thicker radiators have low restriction, and using fewer larger radiators are less restrictive than more smaller ones. One variable is the restriction of the ssd blocks... You could add another pump in series for redundancy and more flow, but I don't think it is entirely necessary unless your loop is using the new alpha cool block and GTS rads.
 
#4 ·
Yes, I know how it works in general, just being so late to the modern wc party. My last water loop was back in 2004 and never since so I'm a bit rusty on performance of modern rads/vents. - What i was looking for is what is the expected heat dissipation per mm/rad "block" - the general 100W/120mm slim (?) rad is exactly what I need I guess.

Regarding the case, can't really find any for 560 rads. Looking at CaseLabs at the moment. Mercury S8S, Magnum SMA8 or TH10A... Targeting dual loops as probably the best solution to rather keep 2 pumps at low rpm than a single one high up with noise.

My env temp is from 22-35, I live in a hot area. Guess 10-15°C delta is fine.
 
#5 ·
I run my d5 vario at 5, which is the highest speed. I can't hear it when sitting at my desk with it on tune floor. A fan at 1100rpm is slightly audible and louder than the pump. My girlfriends vario set to 4 I can barely hear because her room is more silent.

Under 1000rpm the performance between thick and slim radiators is similar. Lower rpm you want lower fin density to let air pass through easier. The faster air speed will cool better. At low rpm, thicker radiators of equal fin density often slow down the air to the point that there is negative impact on cooling, which is why thinner radiators often work equal if not better for silent builds, so long as they are low fpi.

There is very good radiator data here http://www.xtremerigs.net/2015/02/11/radiator-round-2015/
Its a 360mm roundup, but you can scale it up and down a bit... A 480 is a little less than 4/3 of a 360, since the wattage dissipated on the tank ends is the same on 120-480... without doing complicated math, you can get into the ballpark by 2/3 for a 240 and 4/3 for a 480...

I'm not too familiar with the radiator capacity of the cases... but if you can fit 2x480, and 1x360... your good for the dual loop. My general outlook, is better to have more radiator than needed, than to need more radiator and not have it.
 
#6 ·
Quote:
Originally Posted by toncij View Post

Regarding the case, can't really find any for 560 rads. Looking at CaseLabs at the moment. Mercury S8S, Magnum SMA8 or TH10A... Targeting dual loops as probably the best solution to rather keep 2 pumps at low rpm than a single one high up with noise.
Dual loop is a mixed bag. For most people building a gaming rig, single loop is advisable since you will typically be hammering the GPUs at max utilization while most of the CPU cores are idle. If your computer is going to be performing any tasks that will max out the GPUs and the CPU at the same time, then dual loop is preferable since GPUs are in general less sensitive to coolant temp than a CPU.
 
#7 ·
Quote:
Originally Posted by CastleBravo View Post

Quote:
Originally Posted by toncij View Post

Regarding the case, can't really find any for 560 rads. Looking at CaseLabs at the moment. Mercury S8S, Magnum SMA8 or TH10A... Targeting dual loops as probably the best solution to rather keep 2 pumps at low rpm than a single one high up with noise.
Dual loop is a mixed bag. For most people building a gaming rig, single loop is advisable since you will typically be hammering the GPUs at max utilization while most of the CPU cores are idle. If your computer is going to be performing any tasks that will max out the GPUs and the CPU at the same time, then dual loop is preferable since GPUs are in general less sensitive to coolant temp than a CPU.
I mostly do computing (rarely I manage to actually game) and coding to do computing (rendering included since I develop plugins and tools for rendering workflows and farms). What I need of the machine is for it to be as silent as possible while, at times when required, give me maximum burst performance. Most of the time I need low noise, low RPM work (which is probably the irrelevant part) but then I need like 1-2 hours of 100% load on both CPU, GPUs and the memory and drives even (i use SSDs as cache, RAM filler then RAM->VRAM for computing) so I actually kill the machine at those times. That's why my target is as large as possible radiator surface. Two pumps pushin ~20dB is in total ~26dB. A single pumo pushing 40dB is 40dB.
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#8 ·
Quote:
Originally Posted by toncij View Post

Two pumps pushin ~20dB is in total ~26dB. A single pumo pushing 40dB is 40dB.
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...~20dB
unless you buy a Sanso
tongue.gif

the D5s are very quiet, at every speed, so you should "forget" about the pump's noise

for the other request : you need a good rheobus*, not radiator surface (or at least not so much)
or you want a dead silent system @100% load ? In this case, I'm afraid we are in a pinch

* or PWM-fans and a couple of pwm-splitter
 
#9 ·
#10 ·
Quote:
Originally Posted by Cooked CPU View Post

Got money? You do you say, well fine here is the answer to your radiator problem. Buy 1 of this puppy with fans or buy 2 an just add two 180mm fans 1 on top and 1 in the bottom and you are set:

https://shop.aquacomputer.de/product_info.php?products_id=3371&XTCsid=r7rnsld1ctmjdbd9lk0bd5d0kou3c7sn

They are big and very expencive but have an insane high cooling capacity if you set them up with fans
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These are ugly as hell. Hmm, but.... insane cooling capacity passive?
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- Guess with very low RPM fans might be... And I don't need to mess with the bigger case then current R5. Just need to drill holes for the loop to move the water out to this monstrosity.
 
#11 ·
From my experience when you are unsure if you can fit enough big rads inside a case. Well... Go big and put them outside. You can even get rads that is 9x180mm that I know of.

But if you get the gigant, and go for the brackets that can mount 140mm fans you can go below 600 rpm and still have enough cooling imo.

I would have gone for one 180 on top and one in the bottom, both forcing air inside the 4 rads and be done with it
smile.gif
 
#12 ·
Quote:
Originally Posted by Cooked CPU View Post

From my experience when you are unsure if you can fit enough big rads inside a case. Well... Go big and put them outside. You can even get rads that is 9x180mm that I know of.

But if you get the gigant, and go for the brackets that can mount 140mm fans you can go below 600 rpm and still have enough cooling imo.

I would have gone for one 180 on top and one in the bottom, both forcing air inside the 4 rads and be done with it
smile.gif
It's simply too ugly...
biggrin.gif
 
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