Which of these 3 rads (TT 40mm/25fpi, TT 64mm/14fpi, EK 60mm/18fpi)

TT158 · 17 Feb 2021 at 10:22

Hello. I'm trying to decide on a bottom radiator for my O11D XL build. I understand that there should be plenty of space for a thick rad in pull, or even push/pull.

I'm especially curious about the medium thickness / high fpi vs thick / medium fpi comparison. I can only find general statements "high fpi needs high speed fans", etc. and no testing.

I'm planning to run fans at around 1,300 rpm for general use, at which I think it should be fairly quiet at the 3m or so from me the PC will usually sit.

I like the drain port location of the Thermaltake rads, but they're a relatively unknown quantity to me. The EK I guess is the safe option.

Any views on thickness/fpi and general brand quality appreciated. Details of the rads are:

TT CLD360
https://uk.thermaltake.com/pacific-cld-360-radiator.html
406(L) x 119 (W) x 40(H) mm
25f pi
1,000g

TT CL360
https://uk.thermaltake.com/pacific-cl360-radiator.html
405 (L) x 132 (W) x 64 (H)
14 fpi
1,658g

EK XE360
https://www.ekwb.com/shop/ek-coolstream-xe-360-triple-5419
18 fpi
2,050g

ttaskmaster · 17 Feb 2021 at 11:08

Well, thicker rads offer more capacity for heat dissipation, so I'd be looking at the 64mm one in Push-Pull if it'll fit well enough.
I generally prefer low FPI, as you can run a wider range of fans on them and at lower speeds, while still keeping the noise down at higher speeds.

The big factor with FPI is the airflow spread of your particular fan. You want it wide enough that it doesn't rasp on the fins and cause a racket, but not so wide that it stalls in the channels and hampers performance. This is part of why high FPI needs high speed fans, to generate more static pressure and force the air through.
There isn't usually much data available on such things, though, so it's more a case of trying them out and seeing how they do.

For instance, I'm currently using AlphaCool 45mm rads (16 FPI, I believe) and found that EK Vardar F4s are great performers but noisy as all hell, while Corsair ML120s are far more sedate with slightly better performance.

TT158 · 17 Feb 2021 at 20:22

ttaskmaster said:
Well, thicker rads offer more capacity for heat dissipation, so I'd be looking at the 64mm one in Push-Pull if it'll fit well enough.
I generally prefer low FPI, as you can run a wider range of fans on them and at lower speeds, while still keeping the noise down at higher speeds.

The big factor with FPI is the airflow spread of your particular fan. You want it wide enough that it doesn't rasp on the fins and cause a racket, but not so wide that it stalls in the channels and hampers performance. This is part of why high FPI needs high speed fans, to generate more static pressure and force the air through.
There isn't usually much data available on such things, though, so it's more a case of trying them out and seeing how they do.

For instance, I'm currently using AlphaCool 45mm rads (16 FPI, I believe) and found that EK Vardar F4s are great performers but noisy as all hell, while Corsair ML120s are far more sedate with slightly better performance.

Interesting. I never knew about airflow spread. I've just gone on reviews and have Noctua A12s and Arctic P12s.

It's a pity that xtreme rigs isn't still pumping out radiator reviews. I may just go for the EK as the safe option, although I am curious about the TT 64mm. Odd that it's so much lighter than the EK though.

ttaskmaster · 17 Feb 2021 at 21:31

TT158 said:
Interesting. I never knew about airflow spread. I've just gone on reviews and have Noctua A12s and Arctic P12s.

I'm sure other posters will be along to tell you about cars revving in free fall and P-Q Curves, but that's only one small part of a very big picture.

This gives you some basic idea of why it's such a complicated matter: https://www.reddit.com/r/buildapc/comments/25nm7c/basics_of_fan_dynamics/
I work with engineers who specialise in fludi dynamics and aerodynamics, but even they can only narrow it down to an educated guess, really.
Best way to find the best performing combination of rads and fans is really to just test them in your rig and see.

TT158 · 17 Feb 2021 at 22:15

ttaskmaster said:
I'm sure other posters will be along to tell you about cars revving in free fall and P-Q Curves, but that's only one small part of a very big picture.

This gives you some basic idea of why it's such a complicated matter: https://www.reddit.com/r/buildapc/comments/25nm7c/basics_of_fan_dynamics/
I work with engineers who specialise in fludi dynamics and aerodynamics, but even they can only narrow it down to an educated guess, really.
Best way to find the best performing combination of rads and fans is really to just test them in your rig and see.

Looks like a good read! I've skimmed it and will read it later when I've a bit more time to fully focus.

I guess the conclusion is though: test and re-test

Grim5 · 19 Feb 2021 at 21:15

From what I can tell the EK XE 360 is still currently the best 360 radiator money can buy

TT158 · 20 Feb 2021 at 08:24

Yeah it topped the old Extreme Rigs comparisons, but the Thermaltake is new. Probably not better, but curiosity got the better of me and I bought the 64mm version. Will see how it goes!