thx allot for the answer !!!
which is bather SeaSonic or CORSAIR ?
Both are equally good. Seasonic makes their own PSU's and often for others as well (including Corsair). Thus it scores a point extra over Corsair here. Corsair units though are slightly cheaper but of equivalent quality and performance. Basically, you can't go wrong with either.
if you are on a budget but wanted a very good quality hi wattage psu, i suggest you go for the FSP everest 800w. check it out, its really cheaper than any 800w corsair & seasonic but its as good as any high end psu out there. you wont go wrong with that psu.