If I go from an Opteron 2435 D0 to an Opteron 2435 D1, my partners have to do a complete re-qual on the processor, that is how they work.

There are notifiable and non-notifiable changes. Doing a rework with HKMG would be a notifiable change to partners and that would force them into a requal. Requals take several months (complete reression testing on all platforms).

There are minor changes that we do that are non-notifiable (typically only touching one layer), but an all-layer change would force more work for partners. Most would not want to take the part based on the amount of work vs. the short life cycle. If I give them Magny Cours in Q1, then HKMG in say Q3 or Q4, with Bulldozer coming in 2011, they would either wait for HKMG (a bad option for us) or they would skip HKMG.

It's an economic decision, not a technical decision. You may see the change as low risk, but OEMs will not. There is too much money on the line.