Not a bad card I suppose. However nothing entirely impressive either. It seems like the ATI 5450 manages to beat it slightly. Other notebook manufacturers have been able to cram much more powerful cards into a 13" chassis.
They must have a contract with Nvidia, however maybe Nvidia's GPUs really do offer better battery life than ATI's. Apple seems to be pushing battery life over power these days. Nice for the 13", not so much for the larger laptops.
Not likely, from what I've seen from the latest generation of Nvidia and ATI cards, the TDP of the ATI cards are lower while performing better. The TDP of the 320M hasn't been reported yet, however the TDP of the 5450 is 11W, compared to the 9400M's 12W. Since the 320M is the successor of the 9400M, I figure it's somewhere in the range of 10W to 12W.
For non-gamers the graphics performance is completely irrelevant. My MacBook does everything absolutely fine with a 24" monitor attached with a GTA 950 (slowest integrated graphics you can find). Not a gamer, obviously. But many gamers don't care either, because their XBox 3 is fast enough. And GTA 950 is what 90% of Windows laptops sold are using.
But maybe you missed that the new MBP 13" has ten hours battery life. Maybe, just maybe, someone at Apple checked what the battery life would be with a more powerful graphics card and decided that battery life is more important than graphics performance. It is to me.
You mean GMA950, not GTA950.
I'll like to know how you got that statistic of 90%. The GMA950 is a very old, piece of crap graphics chip made by Intel in 2005. Seeing how it's 5 years old, it probably hasn't been sold on any Windows laptop in years. The GMA950 has been replaced by the X3100 and the 4500MHD, and now the GMA (HD) which is in your Arrandale laptop.
Anyway, Intel's market share of the graphics market was 40% in 2005. There's no way that the GMA950 could have been in 90% of the laptops sold that year, and much less today. Most of the laptops bought n 2005 probably have been replaced by now as well.