Hi, I'm buying a Sapphire Radeon R7 240 1GB DDR5 graphics card soon. My current psu is "Zebronics ZEB-450W Value" someone said me that I need to upgrade my psu to fix a graphics card on my pc. Or upgrading my RAM (Now 4GB-8GB) But I still doubt that "do I really need to buy a new psu? Cause current one is only weeks older" please help me guyz