Installed new PSU and caused gpu problems such as artifacts and bsod

Hello

I just installed a new RM1000i psu and moved it into a new case along with all the other hardware that I already had in my old case, I didn't move the ram or cpu, just the entire motherboard and mounted it onto the new case.
I cleaned up my 2 gtx 780tis up a bit and put everything together.
I tried booting up the system but when loading up windows 7 I got graphical bugs that appeared slightly after me entering my password. After a while the system restarts completely. Same happens on windows 8 but the artifact appears before I even see the logon screen.
I narrowed the problem down to one of my GPUs. I removed the one that works fine and tested the one that is causing problems. I've managed to get into windows but the artifacts are still here.
Device manager brings up a whole load of problems:

PCI Simple Communications controller
SM Bus Controller
USB Controller
And the GPU itself, all with the orange exclamation icons.

Tried reinstalling gpu drivers but it doesn't make a difference, it asks for a PC restart and comes back to the same way it was.

Here's an image of the errors, this is taken by phone.

You need to look at cause and effect.
If this problem did not exist with the old power supply, and now it does with the new power supply then the problem would lie with the power supply.

If the old power supply went out in some dramatic fashion (loud pop, smoke, flames) then it is possible it could have damaged one of the cards.

So it must be the new power supply?
What happens if you put the old supply back in?

Also a possibility: dust or crud in the power socket on the video card. Sometimes just unplugging, blowing it out, and replugging will fix that.