seeing that you would like to play battlefield 3 with a 300 Wat psu is pretty low.
I google some cards and looked at manufactures websites, ( Nvidia, Ati ). If you would like to play Battlefield3 (Bf3) i suggest you would upgrade the psu no matter what is in the system. Just so the power supply is not being stressed to overload.
i have a compaq CQ3020IL branded PC which i upgraded the RAM to 3GB and i've put an ATI radeon X1550 PCI-E graphics card to it.... do i need to upgrade my PSU if i want to play battlefield 3 . if yes then what PSU should i get and i am also planning to replace my older card wid an ASUS GTX 550 ti card. what will be the cost of replacing my PSU?