i got problems

some of my pc when i mine monero with claymore 8.1 win 3-4gpu 280x they go shut off

i did clone hdd with 8.1 to others hdd

my power is 2x800w and other rigs is 1250

2 of rig working good with 4 gpu from my 8 rigs

help me

20gb virtual ram
alloc max 100 done