AIO rad....top or bottom of case?

[PhillipM]

What does everyone think?
My old 120mm Seidon V2 has died - the pump went from buzzing to rattling instead - the ceramic shaft has cracked loose - I bonded it back together but in doing so lost the room to sit the magnetic float bearings in - it works without them temporarily* but it's pretty noisy, anyway, I fixed the issue with some lateral thinking - I bought a 280mm AIO instead

The old Seidon only had long enough pipes to go on the rear of the case, the new one can fit top or bottom easily. I was thinking putting it on the bottom as an inlet where it'll get cooler air, compared to the top as an outlet where it's getting warm air from the case......however, doing that means any air might end up in the pump, whereas with it on the top, any air would end up in the rad where it's not hurting much.
Anyone tried both with an AIO?


*On a side note, HOW FRIGGIN HARD ARE AIO'S TO FILL AND BLEED THE AIR OUT OF!
Took me ages. What's wrong with a simple bleed nipple on the radiator?

[Mokey]

I would say put it at the top. It gets slightly warmer air going through it but doesn't dump warm air into the case so should help keep gpu (and everything else) temps lower.

[DoubleTop]

top, heat rises ....

[k3vst3r]

Always top.

[PhillipM]

Right, I tried both
Rad at the bottom as an intake was about 4*c cooler than at the top exhausting hot air - 47-48*c under load rather than 51-52*c - but some air did eventually settle in the pump and it did make a little bit of noise, if the rest of my machine wasn't so quiet it would have been bearable, but I've moved it to the top, where temps are a bit higher but everything is nearly silent, in fact I can't even hear the pump even with the fans off at idle.

The fans are a lot noisier at full speed at the top though - I guess because they're blowing against the case lid instead of into free air - but I'm only using about 50% speed to hit those temps anyway and they're fine there.

Once my new GPU arrives that exhausts air into the case instead of out of the back I might revisit mounting it as an intake, depends how much case temperatures go up by!