More video RAM just means the system can run higher resolutions better. Any more than 1GB video RAM is only really usable if you're going above 1080p.
As for the 2.7GB, that's because it bases it off of DDR1 RAM clocked at, I believe, 200-333MHz. If your video RAM is faster, or you have a newer type of video RAM (DDR2+), then it'll read it as more. Your video card's RAM is likely DDR2 clocked at roughly 50% faster than the graphics standard.
My video card has 256MB GDDR4, with the motherboard having 128MB DDR3 dedicated VRAM onboard. I MAY also have some of my system memory dedicated to it as well - I can't remember. But either way, 384MB VRAM isn't much, but since they're both incredibly fast and advanced (>1GHz), my software reads that I have 3383MB video RAM.
SW-5120-1900-6153
