Changed PSU, now all my case fans run at full speed??

ljt · 24 Aug 2017 at 22:01

I've got a bit of a strange problem.

My current rig contains the following hardware;

AsRock X370 Taichi
AMD R5 1600X
16 Gb DDR4
3 x SSDs
1 x HDD
Zotac Amp Extreme 980Ti

4 x Phanteks SP140 fans (Chasis fans)
1 x 120mm Noctua fan (on NH-D14)
1 x 140mm Noctua fan (on NH-D14)

All the fans are connected to a Phanteks fan controller, which connects to CPU_1 fan header on the mobo

Existing PSU is an 80 plus silver rated XFX 850W XXX edition

I recently purchased a Superflower Leadex 750W Platinum PSU to replace the XFX as I was getting some coil whine from my 980Ti

Anyway, I swapped the PSU over, and now all the fans are spinning at full speed. I've been into the BIOS and reset everything, reset the CMOS, configured the fan curve in the BIOS as they were before, but nothing stops them spinning at 100%.

So I put my old XFX PSU back in and it all goes back to normal, the fan curve in the BIOS works as it should, i.e. under low CPU temps the fans spin down to about 30%

Could the new PSU be faulty? Or am I missing something obvious?

Thanks!

ljt · 25 Aug 2017 at 22:05

Ok an update for anyone interested or having a similar issue!

Using the new 750W Leadex platinum PSU with the phanteks pwm fan hub I've found the following;

With the fan hub connected to CPU_1 header all fans run @ 100%

With the fan hub connected to "CPU_OPT" header all fans can be controlled as per normal with variable speeds (temperature dependant)

Very strange that with the new PSU, the phanteks hub will only work properly on CPU_OPT, on CPU_1 all fans go full throttle, yet using the old XFX PSU on CPU_1 the fans are controlled fine?

Oh well - at least I have a quiet system again using the new PSU!

GTiPUG · 25 Aug 2017 at 22:20

Have you checked BIOS? CPU_1 fan settings are usually defined there..

ljt · 25 Aug 2017 at 22:41

GTiPUG said:
Have you checked BIOS? CPU_1 fan settings are usually defined there..

Yeah initially the settings between changing the PSU's were completely the same.

With my old XFX PSU in I'd set the PWM % to start at about 30% up to 80% dependant on CPU temperature, this was working fine on CPU_1.

I literally just swapped the PSU to the new Superflower one, hadn't changed any BIOS settings and the fans were constantly at 100%.

I "re-detected" all the PWM/Speed via the BIOS with the new PSU installed and it detected the same RPM of the fans for all the % range i.e. 0% up to 100% in stages of 10 were showing exactly the same RPM (1300rpm) where as with the old PSU 30% was around 850RPM, it was now showing 1300RPM across them all.

Swapped the PSU back to the XFX and set it back to original and all was working well again.

At this point I was scratching my head thinking WTF lol

So I thought one last go! but I'll use the CPU_OPT header with the new PSU to see if that made a difference, and it worked!