I think the biggest threat will be ARMv8 in the client notebook/desktop space. Imagine what "good enough" very cheap ARMv8 SOCs could do to Intel margins.............probably at least a year away but think Intel will be attacked by multiple players.... ideas....anyone?
What will ARMv8 do with "good enough" performance that AMD's Bobcat with 64-bit "good enough" performance couldn't do?
Besides NOT having backwards legacy support, that is....
Its amazing how many folks tend to think about how ARM is going to make inroads to INTC market segments. I think a much wiser idea would to ponder what is going to happen when INTC invades ARM space. The reality is they are both going to eat each other market spaces. INTC will always make the better chip. You can wish all you want. IBM is feeding their R/D tech to ARM fabs. INTC is getting into the foundry business. INTC can make ARM chips. What if ARM starts fabbing their stuff on INTC process?
You need to ponder those variables. Also it It amazes me when folks think that INTC is just going to stop making progress in chip deisgn/process tech and just stand still and let ARM take market share.
One other thing every forgets about - ARM is not a fab!