Will GTX 560 Help my OLD Dell XPS 720?

[SdS49r]

Thanks all for your input. The size and psu connections will work (the GTX 8800 is much larger than these new cards) I'm leaning towards the 2-gig card. The only difference I can see between them is the clock speed. How much difference does that make?

2 gig card
Core Clock: 850Mhz
Memory Clock: 4008MHz
Shader Clock: 1700MHz

1 gig card
Core Clock: 900Mhz
Memory Clock: 4212MHz
Shader Clock: 1800MHz