It's better than the old one, but still it's a lowend solution, more for video than games. Though games were taken in to account when it was designed I believe.
Thats not true at all. The X3100 finally has full MPEG-2 decoding capabilities. But it has no deblocking capabilities for any form of video, no hardware acceleration or decoding of H.264/WMV/DivX/XviD.
In regards to video, the X3100 is only slightly better than the GMA950 in that it will lower CPU use SLIGHTLY because it can do more of the decoding work. But when you take overhead and bandwidth into account, because it is a shared/integrated GPU, that point becomes null and void.
The current crop of nVidia and ATI integrated GPUs DO have advanced video features, like video deblocking. Just about every dedicated GPU available, including the ones designed for systems like the MacBook such as the GeForce 8400M GS, offer deblocking, H.264 decoding, acceleration, and deblocking, etc.
Here is a review comparing intel gma 950 , intel x3100 and others in terms of performance and boost
http://forum.notebookreview.com/showthread.php?t=39568
That list is based on synthetic benchmarks and paper specs listed on another website. Not exactly what I would call accurate. Intel themselves have put the performance at about on par with the GeForce4 Ti 4200. Basically, a low-end desktop GPU from 2002.
You can also look at that list referred to in that thread, which is the basis of that threads list, and see that the Intel GMA950 places higher thanks to those synthetic benchmarks than the ATI Radeon Xpress 200M.
I had a Radeon Xpress 200M (with 128MB of dedicated memory) powered by a Turion64 ML-37 (2GHz). Compared to the GMA 950 in my MacBook (backed by a Core 2 Duo 2.16GHz), the ATI card mops the floor with the GMA 950 in real world situations. There were several instances where the Radeon Xpress 200M could push 60fps in UT2k4 with everything set to full running at 1280x800. While the GMA 950 on my MacBook can barely choke out 30fps with everything set to medium at 800x600.
If you browse around notebookreview, you'll find that the X3100 drivers are still very immature and most games do not even function properly yet. Some play, but the majority wont. And you won't get newer games like UT3 or Gears of War. Which the GeForce 8400M GS (that Apple should offer in the MacBook) can play.
It really is sad that Apple is using the worst of the worst GPUs and still charging a premium for it.