IHS iSuppli says AMD commanded 11.8% of revenue for all microprocessor sales (x86 and non-x86) in the first quarter of last year, but that share shrank to 10.9% by the fourth quarter and further decreased to 10.1% in the first quarter of this year. Over the same time period, Intel's share of overall microprocessor revenue purportedly climbed from 80.6% to 82.6%.
Now, IHS iSuppli goes on to point out that Intel and AMD's combined share of overall CPU revenue has grown by 0.2 points since last year, which means the x86 market likely grew, as well. So, the fact that AMD lost revenue share in the overall CPU market implies that the underdog suffered revenue share losses in the x86 processor market, as well, despite largely flat shipment growth (by IDC's count).
Translation: AMD seems to be selling roughly the same number of processors but making less and less money per CPU. I'm guessing the Phenom II price cuts enacted in response to the arrival of Sandy Bridge haven't helped—and neither has the fact that AMD has no desktop chips priced north of $200 right now. The tables may turn by the time Bulldozer processors show up, but that won't be for another couple of months or so.