I'm using MSI afterburner to overclock. I have turned off hardware acceleration in firefox and now it only goes up to 500Mhz. Strange since I did try that before but it didn't work, must have been some weirdness since I then had the card in the lower PCIE x16 slot. Turned out that slot is only x4 speed so moved the card back up to the higher slot. I now have a cpu usage of about ~20% when running a youtube video at 1080p so guess I'll run like this until I figure something else out.
Ouch turns out that that powerusage goes from 75-80w when idle to 120ish when playing any youtube videos
that's just sad...