Solved Power Fluctuates When Desktop PC Works on Inverter

Hi All,

I have a 2KV home inverter which is working flawlessly. But if I have noticed considerable power fluctuation if I use my desktop PC during power outage.
The led tube lights and bulbs start to flicker. The ceiling fan starts to slow down as well. This happens in every room.

I don't face this issue when I am using the PC when there is regular power supply.
I have taken my PC to another location where there is even higher capacity inverter.
I even tried using a UPS and even a power stabilizer (APC Line-R). But, the problem still persists.

Some have suggested that I get a new SMPS.

Do you have any other suggestions which I can try out ?
If all other options fail, I will definitely get a new SMPS and pray it works.

My Specs:

SMPS: Gigabyte 450W
Chipset: ASUS PRIME z270-K
Processor is i7 7700K
Ram: 16GB
No Graphic Card
Windows 10 Pro
1 CD-Rom Drive
Traditional HDD
19" Dell Monitor

All your suggestions are appreciated.

Thanks in advance.

Thank you phillpower2 for responding.
I will get my back up power supply checked.

Further assistance is no longer required as I wish to conclude the thread.

Thanks again.