8-pin PSU problems

[slyexe]

If you have 6 pin PCIE you have 8 pin PCIE.  The only difference is that a 12V is supplied to the last 2 pins for newer cards. Just grab a 6pin to 8pin adapter and call it a day. Otherwise, you CAN buy a 2nd PSU and strictly run that for your graphics cards but 800W should be more than sufficient for that card. 

Check your marketplace for this product:

https://www.memoryexpress.com/Products/MX49724

And if you go with a new PSU you'll just need to jump start it by shorting 2 pins.