You know, part of me wonders whether maybe, just maybe Intel were so desperate in the mid-2000s, what with AMD consistently slaughtering their product line-up across the board (or at least matching it, where Turion and Pentium M/Core 1 were concerned), that they deliberately compromised the security and data integrity of their chips in an attempt to get any sort of advantage over AMD.
Okay, that's probably not what actually happened... but it'd be funny as hell if Intel needlessly compromised their chips in an effort to defeat K10 and Bulldozer, only for it to come back and bite them just when AMD happens to have a very strong competitor on the market.