Intel are now developing 'Larabee' - which will hopefully be a competitior to Nvidias GPU's so it makes financial sense to hurt Nvidia as much as possible as they will soon be competitors not only for onboard but also for dedicated GPU's. NVidia are a much larger threat to intel than AMD as they are a much larger company despite AMD now having ATI under its belt.
Nvidia are far bigger in the computer world than amd, intel and nvidia dont get along, nvidia wont let intel make sli compatiable chipsets so intel spat its dummy out of its pram and said no nehalm for nvidia.
So intel doesnt want to see nvidia grow as a company because it may become a theat, rummors are nvidia nearly bought amd a few months ago