Question Radiator: does air flow direction matter??

[ganymede-]

It comes down to this: does the direction of air flow through the radiator make much or any difference

The rest is just more detailed.

I am stumped and was hoping for some feedback. Building my second build. I have a Corsair Crystal 570X case w a Corsair H100i Platinum RGB radiator system. I had an H100 in my first build that was positioned at the top of my Corsair 600T case. It worked well and I had Static Pressure fans at the top w the radiator beneath it. The fans were pushing air straight down to the radiator This arrangement lasted five years w/o at single problem.

Now working on new build. I have two 140mm at the top of my case which I purchased separately. I still have the two 120mm Corsair fans that come w the H100i.

The 140mm fans on pulling air into the unit. I am debating now as whether I could fit the H100i radiator at the top of the inside case unit.

Now, as a side note the sales guy suggested mounting the radiator in a vertical position. So not sure how to proceed.

 

[ElectrO_90]

Ideally you want to be blowing COLD air into the computer, rather than blowing warm air out through the radiator.
Mounting is also, where it fits in your case without hassle.
The NZXT 500 puts it at the front, which is fine, but still a little cramped in there.