Case fans stop spinning , PSU problem?

[Darksolaris]

I have recently been having a problem with my fairly new computer that I bought on January​ of this year which I got from Cyberpower since I didn't want to build it myself. The problem is that 2 of the 3 fans (not including the CPU fan) often stop spinning at random times or even when I start up my computer. Either 1 fan starts and the other stops then switch roles or both stop. I tried figuring out what was going on by looking at what they were connected to and turns out they are connected to the Power Supply based on checking the BIOS. I figured it's the amount of power but I am not sure if it is.

I have an 800W Power Supply
My CPU Fan is an ETS-T40F-BK ENERMAX
My CPU is an i7-6700k
GPU GTX 1080
Motherboard is an ASUS Pro Gaming Z170

All in case it helps solve the problem.
Any help is appreciated, thank you.

 

[Aeacus]

The make and model (or part number) of your PSU and 2 case fans in question would help the most though.

Fans plugged directly to the PSU will receive +12V all the time and fans will spin 100% at all times. If your fans are acting up, they are dying.
Though, if it were your PSU that has extreme voltage regulation issues on it's +12V rail, by dropping the voltage from +12V to +6V or so (which would slow down fans connected to the PSU), your entire PC would shut down once the voltage drop happens.

Just replace your case fans with new ones and that's it.

 

[Darksolaris]

There's 2 fans on the front, the bottom one which always works and the top one which seems to function normally now ,but the fan at the back seems dead and I might just have to replace it like you said. My power supply model is a High Power HPL-800BR-F14S and my case fans are RaidMax RF-120CT.

 

[Aeacus]

When you get yourself new case fans, do buy a new PSU too. Since what you currently have is a low quality PSU made by Sirfa.

For new PSU, anything from Seasonic will do just fine, in 600W range. E.g M12II-620 EVO, G-650, Focus+ 650 or PRIME 650 80+ Titanium,
pcpp: https://pcpartpicker.com/products/compare/WrNypg,Tc3RsY,R7V48d,nn648d/

M12II-620 EVO and G-650 are good quality PSUs that come with 5 years of warranty. My Haswell build is also powered by M12II EVO series PSU but mine is 850W.

Focus+ is the newest PSU line from Seasonic and it's also good quality PSU. This unit comes with 10 years of warranty and it's size is smaller compared to the other units listed here. It's great for smaller builds where you don't have much room for PSU.

PRIME 650 80+ Titanium PSU is great quality PSU and the best offered by Seasonic. This specific PSU is also the best 650W PSU money can buy at current date.
With PRIME 80+ Titanium series, you'll get the highest efficiency (94%), tightest voltage regulation (0.5%), longest hold-up time (30ms), lowest ripple noise (20mV) and longest warranty (12 years) there is. Fully modular cables and toggle-able Premium Hybrid fan control too.
review: http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=493

My Skylake build (full specs with pics in my sig) is also powered by PRIME 650 80+ Titanium unit. Oh, all semi- and fully-modular Seasonic PSUs are also compatible with CableMod SE-series custom sleeved power cables. To match my black & red theme, i replaced the stock black power cables with CableMod SE-series red colored power cables.

 

[Darksolaris]

Alright, thank you so much for your time and help I really appreciate it. By any chance if you could recommend me some case fans that'd be great but I guess it would just be better to replace them with the same ones and save money.

 

[Aeacus]

For a good and non-LED fan, i suggest going with Arctic F12,
specs: https://www.arctic.ac/eu_en/f12.html
pcpp: https://pcpartpicker.com/product/qCH323/arctic-cooling-case-fan-afaco12000gba01

I have same fans in use in my AMD build. Due to the fluid dynamic bearing Arctic F12 has, it's quieter than your Raidmax sleeve bearing fan and it also lasts considerably longer.