Dave what PSU's specifically are they? The reason I ask is some older variety PSU's don't play nicely with the Z87/Z97 boards (hands on experience at play here), I used the Extreme4 with an i5 4690K and a SuperFlower Leadex GOLD 650W Fully Modular 80 Plus Gold PSU without a hint of issue - It fired up first time every time. With reference to the issue of powering up and powering down - My PC is left on at the PSU (flick switch I position) but when it powers down I switch it off at the wall socket also, again I've never had issue with this practice.
I would think this more likely ^^^ What you have after all is basically a new Motherboard (purchased by myself 14/08/15).
one is a generic PSPower I think but has been running the same CPU/RAM on a H81 board without issues. The one I'm using full time in the server where the board will live is a corsair CX600M. Seems to be ok with the Corsair now so I'm hoping fingers cross I just had something which needed a wiggle or something
Hmmmm lesson learned here (BIN IT!!) Jokes aside, you know where I am if there are any further issues
