I've just built a new desktop – Core 2 Quad with a GeForce 210 graphics card, the Windows 7 Experience Index is: Graphics 3.8, Gaming Graphics 5.3.
However on my 2009 13" MacBook Pro, with GeForce 9400m running Windows 7 via Bootcamp the index is: Graphics 5.0, Gaming graphics 5.4.
Surely that is the wrong way round, the 210 should outperform the 9400m according to http://www.videocardbenchmark.net/
Best Answer
This is mainly guesswork, but it might happen that MacBook Pro has a graphics card with DDR3 memory. That would be considerably faster. Also, the site you linked does not indicate if the version tested has DDR2 or DDR3 RAM.
For example, my GeForce 9500M GS with 512 MiB of DDR2 has a graphics score of 4.4 and a games score of 5.7. Also, the newest nVidia drivers increased my games score by 0.2.