Intel i3 graphis with intel DH55PJ vs Asus 5670?

[Shaheers]

I want to know about intel i3-540 (3.06Ghz) graphics with Intel DH55PJ and if i add Asus 5670
graphic card, what is difference in performance in gamming.

and suggest me a power supply which will be reprimanded and whats minimum?
and also weather i want to upgread my card to gtx 450?

my system requirements are

intel i3 graphis
intel DH55PJ
Asus 5670
500Gb (SA3500418 AS) SATA
Samsung DVD-R/RW

Power Supply should be=?

 

[Aneesh@4GHz]

You will notice the difference in gaming! A CORSAIR VX450 is fine for your setup!

 

[Maziar]

+1^
HD 5670 will give you a drastic performance improvement over Intel HD.
Like Aneesh said,Corsair VX450 is a good choice.