For Dell, selling AMD would be a huge problem. Sure, at least to start with, AMD would cut them a massive discount (just to get a foot in the door, and in particular so as to finally cross out the one and only top 10 manufacturer that has never used a non-Intel CPU) but only to start with. After a while, AMD would start charging Dell a market price.
Much worse, Intel would start charging Dell a market price. This would be a huge problem for Dell - a firm, after all, which wouldn't know a technological innovation if you shoved one up its backside sideways, and has no other real claim to a seat at the top table other than its ability to move a lot of boxes engineered by other companies and heavily subsidised by one particular other company (Intel).
Without the massive Intel subsidy, Dell are dead meat.
Even with the subsidy, they seem to have hit the wall. What are they going to do now?
Either they come up with something brilliant (what? beats me) or else they come back to the field with a bump. They didn't get to be #1 by being totally stupid, but life without an Intel cash cow propping them up looks like a pretty bleak prospect. They would be very hard pressed to stay in front of the competition - in particular, Acer, which is making a big push at the moment, and looks set to overtake IBM/Lenovo any day.
Lenovo, BTW, are going to have to get cracking on a game plan Real Soon Now. If they just drift along, or (worse) if they start cost-cutting and dumbing down their quality, the creditors will start leaning on them and they could be in big trouble.