well i think i've got it.
but can you suggest me a socket 1156 motherboard for i3 processor which can do a crossfire (x16, x16) for 2 HD 5770s. Please suggest me a budget motherboard
let me reiterate myself. For a single 5770 card configuration
your 550 W PSU is more than enough for 2 X 5770s it may be cutting it close.
From the ATi/AMD website
600 Watt and two 6-pin connectors for ATI CrossFireX™ technology in dual mode