Yes, it's clear that Intel wants to make security a top priority. However, this article still doesn't explain why acquiring McAfee in particular makes any sense, especially at a cost of $7.7 billion.

Yes, it does say that the "McAfee purchase gives Intel an instant foothold on countless PCs," but these are not the PCs that Intel is after. These PCs already have Intel chips on them. Intel presumably wants security as a headlining feature for their next generation chips to entice users to upgrade.

In addition, Intel can gain an even wider-reaching foothold into your PC by bundling a driver and distributing it through Windows Updates, as it does already with its integrated video solutions. They presumably wouldn't need to pay Microsoft $7.7 billion for the priviledge of making Windows more secure.

Aside from the foothold in your PC, then, what is left of the "long-term, strategic buy"? There might be some patents and some talented developers, but for a company that already spends $5 billion on R&D every year, it's hard to understand why Intel couldn't come up with an in-house solution.

No, the real reason why Intel bought McAfee is probably much more pedestrian: Intel is simply sitting around with too much cash earning too little return.