no. they both have the gma 3100, the gma 3100 is derived from the gma 950.
the g965 has the gma x3000 , (the q965 and 946gz used a core derived from this). x3000 is unified shader based and the gma950/gma3100 are not.
the only 3 sreies that will have something derived from the x3100 is the g35 whenever it finally comes out.
i have a g31 btw, and had a 946gz and g965 for a bit. the g31 vs g33 main difference really is ich7 vs 9 (and a real ide port) and the g31 can only have 2 ram slots instead of 4.