is nvidia gts 450 compatible with my rig?

[lorenz417]

cpu:intel core 2 duo e6600 2.4ghz
psu: 500W
mobo: asus P5G41T-M LX3
HDD: 500gb seagate
monitor: samsung SyncMaster 920nw 1440x900

questions:
1. could i use the hdmi cable to connect my video card to the monitor? would that matter/make a difference? or should i just use the dvi cable?
2. can my psu handle the gts 450? it says on the specs that it's minimum power requirement is 400w. what does it mean?
3. i'm planning to play some games like need for speed: shift 2 unleashed, battlefield 3, gta iv. is gts 450 enough to run these games smoothly?

thank you in advance for the answers! sorry i have so many questions. i'm on a tight budget

 

[SmurofNeves]

HDMI is nice for connecting to a larger full hd screen if possible , on your current setup I was just gonna use the DVI..
As far as the powersupply, you can support the card with ease don't stress...
For the gaming the card is 100%, I'd advise to move the CPU up to one of the quad cores/I series CPUS.

But you'll still be able to play on decent spec,,