I don't know how old or new my copy is - but for example it will show GeForce FX 5900XT properly with 128MB memory (same page you have the V3 on), but if I have a V2 installed at the same time it will show "FX 5900XT, Voodoo2" as the 3D accelerator, and just show "256KB or more" for video memory. The only ATi cards I've tested are fairly new - Radeon X or higher - and they all show 16MB. I don't have anything pre-Radeon to test with. I've wondered though if that isn't deliberate on the card - like it's only reporting 16MB in VGA mode for compatibility or some such (since it does tend to accurately tell you what GPU is there).
As far as GPU-Z and other detection utilities like that, they tend to work for newer "known cards" - I've never gotten it to accurately show my 3DLabs cards, however, and it isn't fully accurate with the 5800 Ultra. They actually have a list on the TPU website that shows every card it's compatible with. With Aida at least it will pull the BIOS string off the board and gives you enough that you could probably get reasonably close with some web searching.