The thing to remember is that its going to be shared memory, and most IGP's memory access can be limited in quantity. That being said, the IGP doesn't care a bit when you are loading a large spreadsheet or what-not. This requires no shaders and generally won't even have a measurable impact on your CPU. If you are worried about it, set your IGP memory down to 128 MB.
Minolta 50/1.4, 17-35/2.8-4, 24-105/3.5-4.5, 35-105/3.5-4.5, 80-200 HS APO G, 100-300 APO
Tamron Di 90mm/2.8, 28-75/2.8