So I removed the solder mask from the entire back side of the pcb with some 1000 grit sandpaper. The difference is incredible! I have had it running now for ~35 min and the heat sink is now as warm as the top pcb, the pcb is not hot any more! Looks like it's time for some overclocking!
I used what I had on my desk rubber bands and chipset heatsink
But it works! I'm only using the thermal sheet between the pcb and heat sink. Power is going though some of the vias and will short to the ground plane if it contacts the heat sink. If I can find one of my ir thermometers I will post some temps.
Edit: I just ordered some oscillators and 0805 resistors, I'll post back when I get some results.
I used what I had on my desk rubber bands and chipset heatsink
But it works! I'm only using the thermal sheet between the pcb and heat sink. Power is going though some of the vias and will short to the ground plane if it contacts the heat sink. If I can find one of my ir thermometers I will post some temps.Edit: I just ordered some oscillators and 0805 resistors, I'll post back when I get some results.