There is a major GPU upgrade in these new Symbian devices.
Dedicated graphics memory is upgraded from 32 MB (N8, E7 etc) to 128 MB. As it's dedicated GPU separated from the main ARM CPU you still need to be aware of some tricks to keep the GPU hungry and not to upload any textures in the main rendering etc.
Graphics memory upgrade will definitely give more space for textures and augmented reality should be much easier now.
Graphics performance is also boosted from 200 MPixels/s to 1000 MPixels/s! As the screen resolution is still the same NHD this will give a lot of per pixel performance for heavy shader effects.
It does not hurt that the CPU is also 1 GHz now and there is 512 MB's of RAM in these devices