On one side on mine I have an Enermax Magma and on the other I have the Corsair fan which is some rebranded thing but I forget where from.
They're not in sync, different max speed, air pressure and volume also:
The Corsair is on the the CPU_FAN header and the Enermax is on a case fan header.
At idle the Enermax actually switches off but stays spinning because the Corsair is on low the other side pulling air through
Idle temps are ~25 degrees, load temps less than 50 degrees, ambient is about 19. Oh and thermal paste is stock.
Why is sync important?
Irregardless:
Akasa Apaches have now dropped to £9.98 each - they are PWM
Also get
Akasa PWM splitter to run them both off the CPU_FAN header if you like.
I dislike whacked colouring on fans but those have "the best" specs on them and fit the bill - take with a pinch of salt as I swear all fan manufacturers use different standards.
Other PWM fans:
Noiseblocker BlackSilent Fan XLP £8.04
Scythe Kama £9.19
Noiseblocker Multiframe S-Series £17.99
Noctua doesn't have a PWM fan so I'm not sure what you meant there.
I'd suggest to get fans you like the look of
