I assume that this translates into a G4500 or G4500HD chip. Their main difference is that the later supports accelerating HD movies, while the former doesn’t. Both use shared memory, so the amount of reported memory does not make any difference.
Make absolutely sure that the laptop does not sport a GMA 950, however, as this has absolutely terrible driver support on all platforms!
On Windows, expect something close to OpenGL 2.0 without any support for offscreen rendering (either FBOs or pbuffers). There is no support for OpenGL 3.0+. DirectX should be at version 10, but way too slow to actually take advantage of DX10 features.
On Linux, the situation is slightly better with regards to OpenGL. The drivers support FBOs and, if I remember correctly, they advertise OpenGL 2.1. Some OpenGL 3.0 features are being worked on, but a full implementation will not surface in the immediate future.
These chips should be good enough for regular desktop use, including HD movies (if you have a fast enough CPU). There have been reports of instability on Linux, but all upcoming distro releases (October) will feature significantly improved drivers.
However, Nvidia IGPs like the 9400 and Ati IGPs like the 3450 trounce Intel’s offerings in all fronts: speed, driver stability, OpenGL support… If you are planning to do any serious graphics development, avoid Intel’s IGPs at all costs.