Gaming pc assemble help

[nikhily2j]

i want to assemble a gaming pc in which i can play games of coming 3 years.....by budget is $400 and i want to purchase only cpu,motherboard,gpu,psu,ram,hdd.
for graphics i have selected ati readon 7770,6850 and 6790.
1.if i want to buy 7770 then which brand to buy his,asus,sapphire,?
2.which is good 7770 or 7770 oc?
3.what is crossfire and how to do?

also suggest me cpu,mobo,hdd,ram,psu..........n how to select motherboard?

help the Junior

 

[Emelth]

$400 to get all the stuff u want wont really work, all the stuff you will be able to purchase is already 2-3 years out of date and i would say be barely even play games on low settings