Wouldn't the logical thing to do is to start mass production of 40nm parts while minimizing production of 55nm while that inventory keeps trickling down, and introduce 40nm with a hard launch once 55nm inventory is at the desired level?
Of course, if yields are still quite low and improving very rapidly, then there's good reason to delay 40nm production as much as you can - which clearly complicates matters greatly... I'm not sure they'll be improving so rapidly (on the matter of just one month or two) that it'd matter as much as you could naively assume, though.
As for AMD ramping wafers, I'd *guess* it's mostly RV740/RV790/RV730 at this point, with most of it being the first. I would suspect that they cut production more than consumer sales were really reduced (i.e. at or below the level of inventory replenishments in the supply chain which were clearly insufficient), so now they need to increase production back to meet the real channel sell-through (i.e. consumer spending).
Of course, if yields are still quite low and improving very rapidly, then there's good reason to delay 40nm production as much as you can - which clearly complicates matters greatly... I'm not sure they'll be improving so rapidly (on the matter of just one month or two) that it'd matter as much as you could naively assume, though.
As for AMD ramping wafers, I'd *guess* it's mostly RV740/RV790/RV730 at this point, with most of it being the first. I would suspect that they cut production more than consumer sales were really reduced (i.e. at or below the level of inventory replenishments in the supply chain which were clearly insufficient), so now they need to increase production back to meet the real channel sell-through (i.e. consumer spending).