will a 850 watt psu be sufficient for my system?

Big foot Wallace

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Jul 17, 2014
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I recently ordered a gigabyte radeon r9 280 (not 280x just 280) and a Ultra 850 watt PSU. I see that the psu has 4 +12v rails at 17 amps on each one.
So 68 total amps? Will that be enough for my card and will the wattage of the psu supply enough for my entire comp? My specs
AMD Phenom ll x4 810 Processor
Gigabyte Radeon R9 280
8GB Ram
Ultra HS850 Modular 850 Watt PSU

I used a wattage calculator and my rating was around 650 watts for the whole system but im still not sure and i would hate to burn up something that i just got lol