psu of hytech
how many amperes on the +12v rail?
look at the side of the psu, there should be a ratings chart. find out what does it say under +12v or if the psu has more than one +12v rails e.g. +12v1 and +12v2 or +12va or +12vb or so on.
if it doesn't have enough amps, upgrade the psu and you could fit more powerful cards.