The affect on AMD is not going to be as great as it would be compared to nVidia.
AMD is already producing CPUs with very capable IGPs anyway. The eventual elimination of socket AM3+ to be replaced by socket FMx will mean that AMD will only be producing their so called "APUs" for the consumer market.
AMD can still produce low end graphic cards because they can hybrid crossfire with their APUs. The market potential will be somewhat small unless AMD can increase their presence in the desktop consumer market. nVidia must basically abandon the low end graphic card segment since there will simply not be a need for them. nVidia's lowest end cards would probably have to be at least 15% faster than either Intel or AMD's IGP to be able to garner sales (at least to informed buyers).