Is canyourunit inaccurate?

So I was checking to see if I could play Metro 2033 and it says I can play it. However, it thinks my video card has 2.7 GB of video RAM when in actuality I only have a 1GB VRAM video card. Also, according to the site, I'm only running DirectX10 but dxdiag says my system has DX11...can anyone explain whats going on?