Hmmm....so you think this is a power issue? I based my system from what I found on the internet. This sucks.
Dunno, if thats the case you should be able to set a lower clock, reboot the thing and then it would work.
Did you ever make a screenshot of your pool config page? I'd like to see it.
Assuming it's a B8 running at default 800 watt's is not enough to run 2 blades. That is a 1000 watt psu only on 220/240 so would work fine there.
But he will have to underclock to get 2 blades running with 800 watt's. It might not be only issue but it is for sure at least one issue.