how much watt do i need for my system ?

[mo7amed3211]

motherboard : H61M-D2P-B3
Processor : Intel Core i5-2400
Ram : 4 GB ( i will buy 8 GB soon )
graphic card : msi 9400 GT ( i will buy Gigabyte hd 7770 OC soon )

i am using currently 400w and i don't know what's the PSU name
i will buy Cooler master and my question is can 500w handle my system and handle 8 GB ram and gigabyte hd 7770 OC ? or should i get 600w ?

 

[gert21445]

Hi, a good-quality 400W power supply should be more than enough to power your current system, as well as the future upgrades that you have listed.

Cheers!

 

[mo7amed3211]

i am still worried about my old PSU ..... i mean i don't know if it's a good PSU or not.