AIO radiator placement

[lithium_6]

I don't have any experience with AIO coolers, a few days ago added a fan controller in a Ryzen 2600 build. Just by adding a fan controller (my gigabyte motherboard only had one extra header and I was suspecting that my Y splitter could not fully power all the fans (3)) I saw an overall drop of 10°C, now the CPU runs below 80C under load. This made consider an AIO for another build that I have.

 

This build is a Ryzen 7 1700 with the stock cooler. It usually runs in the high 80°C under load so I was thinking in adding an AIO, probably an ML120L from Cooler Master. The ambient temperature is around 26-33C in the summer. I already clean the stock cooler fins and replaced the thermal paste.

 

My question is over radiator placement, how bad is to place the radiator at the rear exhaust instead of top exhaust?

 

In this build I'm running two 120 mm intakes and one 120 mm exhaust. So if I place the AIO in the rear I would have 2 intakes, 1 top exhaust and 1 AIO rear exhaust. 

 

If I placed the AIO on top I would have 1 rear exhaust, 2 intakes and 1 AIO top exhaust.

 

I know that hot air raises, so this is about what is more efficient. Rear or top radiator mounting?

[Hairless Monkey Boy]

11 minutes ago, lithium_6 said:

It usually runs in the high 80°C under load

That temperature isn't to bad 90C+ is where I start to be concerned.

11 minutes ago, lithium_6 said:

probably an ML120L from Cooler Master

I wouldn't bother with a 120mm AIO. Many air coolers exist that will easily outperform it. Minimum I'd go for a radiator is 240mm.

12 minutes ago, lithium_6 said:

how bad is to place the radiator at the rear exhaust instead of top exhaust?

It would be very similar. Only thing different, is that you should be sure to mount the cooler with the tubes at the bottom, but as I said, a 120mm AIO is not worth it.

[lithium_6]

20 minutes ago, HairlessMonkeyBoy said:

That temperature isn't to bad 90C+ is where I start to be concerned.

I wouldn't bother with a 120mm AIO. Many air coolers exist that will easily outperform it. Minimum I'd go for a radiator is 240mm.

It would be very similar. Only thing different, is that you should be sure to mount the cooler with the tubes at the bottom, but as I said, a 120mm AIO is not worth it.

I was considering the 120 for the rear exhaust but if placing the radiator at the top of the case doesn't make a difference in efficiency (hot air raising) then I would consider a 240mm

[Hairless Monkey Boy]

5 minutes ago, lithium_6 said:

I was considering the 120 for the rear exhaust but if placing the radiator at the top of the case doesn't make a difference in efficiency (hot air raising) then I would consider a 240mm

I don't know if anyone has tested this, but I would guess the difference would be within the margin of error. 1-2C at most. A larger radiator will make a much greater and measurable difference.

 

Go with a 240mm or larger if anything, but also consider an air cooler. There is something to be said for the decreased complexity and added longevity, and the performance is similar in many cases.

 

And this is from someone who has a full custom loop.