gigabyte z97x gaming 7 issues

Hi everyone.

I have just upgraded my PC, I'm running the gigabyte z97x gaming 7

My first issue was that my PSU only has a 4 pin to power the CPU but this mobo has the 8 pin but I plugged the 4 pin into it, it looks like its running OK. (Running batman arkham knight with no problems) so is this safe or do I need to upgrade PSU?

The second thing is that sometimes the PC doesn't power down properly. (Fans and lights stay on)

I'm not sure of this is related but, oddly, if I touch a key on the keyboard when the PC is off. The keyboard lights up for a couple of seconds.

Thanks in advance for your help

Tippee