External Radiator

[UltimateAlloy25]

How much more efficient would it be to mount the radiator of an AIO cooler on a wall near the PC instead of directly on the PC? Would it make a difference? 

[WinNut]

It would make a small difference as the air cooling the radiator will be cooler than if it was in the PC, as the air from the PC is heated by the GPU (assuming that the rad fans are exhaust).

 

Doing that would make a good heater in the winter.

[QueenDemetria]

How much more efficient would it be to mount the radiator of an AIO cooler on a wall near the PC instead of directly on the PC? Would it make a difference? 

Not really, if there is any difference it will be slight.

[VincentC]

Noise will increase significantly, performance will increase marginally.

[Faceman]

Well.. depending on what GPU Cooler/Heatsink you are using, it might be better performance gains than you'd expect.

 

Some GPU Heatsinks/Coolers are designed to blow air out the side and around of the GPU, instead of exhausting out of the rear.  All of that hot air has no where to go but up, and thats exactly where my radiator is. One such heatsink that does this is the ACX Cooler on many EVGA cards.  When I had my radiator up top in my case with the ACX Cooler below, my CPU temps would increase by as much as 11C!  When I finally did the G10 modification to my GPU and got rid of the ACX Cooler, my CPU temps dropped by a staggering 11C. 

[UltimateAlloy25]

Well.. depending on what GPU Cooler/Heatsink you are using, it might be better performance gains than you'd expect.

 

Some GPU Heatsinks/Coolers are designed to blow air out the side and around of the GPU, instead of exhausting out of the rear.  All of that hot air has no where to go but up, and thats exactly where my radiator is. One such heatsink that does this is the ACX Cooler on many EVGA cards.  When I had my radiator up top in my case with the ACX Cooler below, my CPU temps would increase by as much as 11C!  When I finally did the G10 modification to my GPU and got rid of the ACX Cooler, my CPU temps dropped by a staggering 11C. 

Just cooling the CPU, gonna use H105

[Bosco]

What kind of gpus are you running? If its something like dual 290xs or something it would make a bigger difference then say a 970. does the h105 have long enough hoses to mount outside of a case?

[UltimateAlloy25]

What kind of gpus are you running? If its something like dual 290xs or something it would make a bigger difference then say a 970. does the h105 have long enough hoses to mount outside of a case?

a 970, eventually gonna sli a second one though

[Benji_w]

Would be much easier to just improve the airflow in your case tbh, but just my 2 pence.