sounds like a PSU issue. I have a Corsair C600M with 552W of 12V power and it ran an overclocked antminer without problems. However, not all power supplies can push full capacity for 24/7 and some may not be able to hold more than 80% of the peak rating for a long time.
Try disconnecting power from the secondary blade and try again. If the device runs 90GH without problems but is having issues with running both blades then its a PSU issue
I have a Corsair 500 CXM lined up for one Antminer. I read at over clocked they pull 400w. Will this PSU be good enough?
Its a gamble, since there is only 450W available on the 12V rail. You might get away with stock speeds, but if you overclock it theres a high chance you will get chips disabling, random reboots, or low hashrates from a lack of wattage over 12V