Is there any voltage stabilizer for PC?
Your PSU should be able to work across a wide input voltage range. As you have not mentioned any adverse effects since the fluctuations began, I'm gonna go ahead and say you don't really need a voltage stabilizer as such. Eg spec sheet, compare your own:
UPS acts as a voltage stabilizer...
I've never seen a UPS with that feature in the specs, care to provide a link?
My old APC would happily accept low voltage and keep going, but the new MicroTek disconnects from mains and switches to battery if the voltage ever drops.
If your PC is not switching off now, getting a stabilizer may actually be detrimental as it might cut power to PC if it senses the input to be outside it's designed safe window.
I've bought and setup a microtek UPS + battery when I build the PC but discarded it later as it was making constant buzz noise during operation which was bothering at night
I have the very same issue with MicroTek Twin Guard Pro+ UPS. The buzz is quite loud!
@lockhrt999 this is not fan noise, it's just continuous normal operation noise. If it's disconnected from mains the noise goes away. APC was not doing this, so I assume MT cheaped out on components.
End of the day, get a UPS for safe shutdown during power cuts, and use spike busters for added protection from lightining strikes. And just because you have a 1000W PSU doesn't mean you need a 1000W output UPS. Even when gaming both your CPU and GPU won't be under full load and consuming max power. So if you can measure your actual usage, you can buy based on that instead of going overboard.
For reference, my 1000VA (600W output) UPS could support OC'd 3770k + 980Ti and 12400 + 3070 TI while gaming powered through a 850W PSU.