I have decided to buy a AMD R9 270x but I m in a doubt ,so here are my PSU specs..
huntkey 550W ATX12V v2.3 @ EPS12V v2.91 power supply
will it be enough ?
Yes your system should only draw about 450 watts at load. 450/550= 80% watts used for you power supply so a 550 watt is pretty much perfect since is stays at the 80% load range so your PSU will last longer.
A 550w power supply is enough to handle that GPU, and it also gives you a tad bit of headroom. Im not fimilair with that PSU though. If its not bronze verified id replace that with a bronze certified PSU.