Around 10 - 12 years ago, when Dell was really starting to emerge as THE mail-order OEM, there was a rumor that Dell's boxes were literally built and configured by Intel.
As I think back, that might be true. Intel wasn't marketing motherboards then, and it had to start someplace.
Dell has always had very close ties to Intel, and it really is a sea change to see Dell (and for that matter Sun) move toward AMD.