The side panel has this for Amperes per rail.
3.3 - 15A
5.0 - 15A
12V - 18A
So in round numbers at max this would be 45+75+216 or 336 Watts.
There are thousands of better PSUs and since I can't pick one for you due to the Earth being a big place, come back with what you can buy and we'll pick it over.
Be sure to pick something in the 450+W size with a Single +12V Rail.
I built my system using Gigabyte ga-78lmt-usb3 v6.0 motherboard and AMD FX-8350 processor. I have two 4 GB RAMs connected to it. SMPS is iBall pps 255 which is of 450 Watts. I am getting continuous short beeps on running the system. It automatically crashes after continuous short beeps. On checking the beep codes for award BIOS system I got to know that it indicates Power supply unit failed 2.AMI BIOS. Which SMPS should I buy to resolve this problem? Is there anything else that too may be leading to this problem?