PC keeps restarting randomly

[Matthiew]

Hello everyone!
My friend's computer yesterday began to restart at random times, after a cpu change from G3220 to i5 4460, and a bios update. His motherboard is a ASUS H81M-K. We updated the bios, then swapped the cpu to the 4460. We noticed some bend pins, but it was working before, so we just put in the i5, then turned on the machine. Everything was cool, until the "Display driver stopped working, then restored" thing happened like twice every minute. We updated the drivers for his gtx1050ti(4gb) for the latest ones, then this problem was gone. Then it started to randomly reboot itself. It seems like it doesn't matter if the pc is under heavy load or not, it reboots. The temperatures were okay, the cpu was around 45C , the gpu was at 60C at load. The voltages looked okay as well. He have some crappier type of 400W PSU, but it should work, as it worked well before.
What should we try? We don't want to bend the pins back until it's not 100% that those cause the problems. I was thinking about reinstalling the system, as the current system lived through a cpu swap, a video card swap, and both 2 ram stick swap. But i'm afraid that during the installation it might restart at a point, so we will be pretty damned.

[ImNotThere]

Whats your psu? Like brand and rating

[Matthiew]

I really have no idea, it's a 400W noname basically, which came with his 30$ case. But it served fine, with no problems.

[ImNotThere]

7 minutes ago, Matthiew said:

I really have no idea, it's a 400W noname basically, which came with his 30$ case. But it served fine, with no problems.

It sounds like a crappy psu problem tbf, try using a different psu also quote me to make sure i see any replys 

[Alpha297]

If it's a windows system, you check the Event Log and see if it gives you anything to go on, but my first inclination is the PSU as well from your initial description.  If you haven't in a while, it wouldn't hurt to take a can of air to the PSU and system and make sure all your internal connections are good and tight.  

[genexis_x]

9 minutes ago, Matthiew said:

I really have no idea, it's a 400W noname basically, which came with his 30$ case. But it served fine, with no problems.

Change the PSU ASAP

Also don't cheap on PSU

[Matthiew]

Why just now, after the cpu upgrade? Isn't it has something to do with it?

[Alpha297]

Just now, Matthiew said:

Why just now, after the cpu upgrade? Isn't it has something to do with it?

A new CPU would change the power characteristics of your system and if the PSU is bad (gone bad, or bad design in the first place), it may not be able to provide the new requirements.

[Matthiew]

Just now, Alpha297 said:

A new CPU would change the power characteristics of your system and if the PSU is bad (gone bad, or bad design in the first place), it may not be able to provide the new requirements.

And how about the bend pins? 
I just want to make sure that it's the PSU, because we don't have any spare PSU to try with it, and we don't want to "waste" (obviously not waste) money on that, if not that thing is the problem.

[Matthiew]

Okay, he sent me this, and i did some calculations on a psu calculator. It was 18,8A on the 12V, which was barely enough, but with the i5 4460 it jumps to 21,5A, so this might be the thing.
Okay, so maybe we can borrow a normal psu and test it, i will report the results here, thanks for the help!

[Matthiew]

I'm writing from that computer that we are talking about, with the original PSU. I wanted to see how much load can this akyga masterpiece take, and after 1,5h stressing it didn't restarted. However, the display driver fail still happening randomly, but it wasn't happening before the cpu upgrading and bios update. What now?
(also some cpuid stuff if someone can pick up something useful from this.)