The Nvidia 7400 is technically a dedicated video card. It is not onboard. The Nvidia card is powered by itself. It only requires the extra memory when needed, therefore taking from system memory. Ie) in games when needed. THE GPU does most of the work im games to begin with. This is good to have a card like this, that way the GPU only really runs fast when it needs to, therefore saving battery life.. The thing can run Half Life 2, try running it on a normal Mac Book or with Intel video in that matter.
The 7400 Go is far more superior than the Intel Video, and I am sure Dell included the 7400 with this new laptop for a reason. That reason being peformance versus power requirements, they designed a very mobile machine and slapped the best possible graphics card to allow for good battery/mobile peformance. There is no use on including a huge power hungry GPU, and getting less than an hour battery life. Also look at how small the 1210 is, I am sure it was a hard task to cram a decent GPU in such a small machine..
People think Ram on a video card makes the world of difference. The tests show it. going from a 128 MB card to a 256 mb card means shit all. It depends what powers the GPU and how efficient it is. Having more ram on a GPU can mean only a few frames for second. Versus a better GPU chip which could mean 20-40 more FPS..