Well, if I had your 'old' machine, that would be like my new one...
I don't know if the advanced video card would make as much a difference as the speed of your internet connection. But it runs fairly decently on my MBP 2.2ghz (SR) with a mere 128 vram. Hell, I remember the days when my Mac G3 tower (first blue and white models) had a whopping 32 mb of vram, and I ran some cool games on it...