I believe some features will be available even if the video card has less than the minimum 512 MB. Are you planning to use the 3D modeling features? If so, those definitely DO need at least 512 MB of VRAM.
If you're not sure what features you'll be using, nothing is stopping you from downloading it and trying it yourself (Photoshop can be tried for 30 days free). That's what I suggest you do, to be sure.