Is this enough power for the Video Card

[pgb205]

Bought Gigabyte Radeon HD 7970(GV-R797TO-3GD)
http://www.amazon.com/gp/product/B008WAMV3Y/ref=oh_details_o00_s00_i00?ie=UTF8&psc=1

I will use it with my Biostar A770E3, AMD Athlon X3 450, two harddrives running Win7.

Current PSU is Antec TruePower 450W.
I never had an issue with the PSU, but GPU minimum recommended is 650Watts. I'm wondering if I will be able to get away with 450W or am I really pushing it?

If this is definitely not going to cut it what would you recommend for the card?

Also, my assumption is that this PCI-E 3.0 card will work in my motherboard, which only has PCI-E 2.0 slot.

 

[akensai]

PCI-E 3.0 is backwards compatible with PCI-E 2.0. Furthermore, no GPU can saturate the full bandwidth of the PCI-E 2.0 x16 slot as of yet.

As for your question, you are going to need to update your PSU. You may be able to boot with the 7970 if you are lucky but once it starts to pull a little at load you are likely to see PSU failures and shitdowns.

I would HIGHLY suggest you go at least 600w for the 7970 with 750w+ being recommended. It's a very power hungry GPU.