I have a very odd question on GT AP-15's. I'm running a XSPC RS360 radiator with 3 GT's in a external rear vertical mount. Top fan location shows as Radiator 1, middle fan is Radiator 2 and lower fan is Radiator 3 (see snip attached) which shows HWMonitior.
Notice how the middle location is approx 100 rpm lower than the other two? This happens in either a pull or currently as a push setup. I thought I may have a bum fan after remembering this was the same case when I had two of these on a mugen in P/P. Pull side always read lower than push but thought nothing of it till mounting on this radiator. With all three in push or pull same results.
Now here's the odd part. I ordered a replacement fan and just installed it, that is why there's two snips combined into one. Left side is with new fan, right side is with old fan that I thought might be going bad. Look again at Radiator 2 rpm and tell me why this is. Could it be something with radiator? Or common when mounted on a radiator?
The case does have a rear exhaust (which is only running 60% at 1200 rpm) which is in line with the upper mounted rad fan and the lower mounted PSU also just partially inline with the lower rad fan but it barely has any output that you can feel.
I'm lost as to why the middle rad fan is always 100 - 125 rpm slower than the other two even with a brand new fan. Any thoughts?