@Junko - The only logical conclusion to that question is that AMD feels that ARM provides something that x86 cannot. AMD is a member of the exclusive club of 2 that can make x86 processors so for it to give up all the advantage of the established ecosystem around x86 to move to ARM is a testament that they feel they can compete better with ARM CPUs.
They did try low power CPUs with bobcat but probably found the ARM CPUs to be much better at the low power level. At the high end where it is performance at any cost they will still bring out x86 cpus.
Actually till now most of the ARM comms players have been smaller fry. bigger player can grab market share through non technical advantages like easy of availability, larger user community, lower MOQ, no NDA requirement. Try getting datasheets for comm processors from Cavium or Broadcom as a small oem !
I often ended up with Freescale even though there were better parts around simply because You could whip out a credit card and order dev kits or samples.
On a tech note, not sure what AMD gains by going ARM. probably marketing and SW Eco system reasons. The x86 ISA decode penalty is a non issue these days.
If AMD can move these parts through commodity channels and make their availability ubiquitous, they have a good chance of a 10 -20% market share. But execution s everything and that seems a big ask for AMD these days. Would also help if they went open with their freedom interconnect.
What would also be interesting is repurposing the GCN for packet processing, ala IXP/Netronome
Not sure how AMD will differentiate with other ARM providers. Rick, you did not mention X-Gene from Applied. It seems they have similar features in term of core count and interfaces and have silicon today.
There are also the existing PPC and MIPS players in this crowded market, do you think ARM or x86 will gain market share there?