Like the tides, the AMD buyout rumor returned yesterday, this time with Dell as the alleged buyer. And yet again, the stock market dutifully responded by moving share prices around as the speculators who started and stoked the rumor no doubt took their gains. There are so many problems with this rumor whenever it arises, but the two main issues are (a) it's hard to see a good rationale for any other tech player to buy AMD, and (b) Intel wants to make sure that AMD stays independent and viable (although not too viable).

What sparked the buyout rumors this time was a train of high-level executive exits at AMD, starting with CEO Dirk Meyer's departure last month. COO Robert Rivet and SVP of Corporate Strategy Marty Seyer announced last week that they'd be following Meyer out the door, prompting speculation about what, exactly, is going on at the chipmaker. A string of high-profile exits is always a bad sign, but it doesn't have to mean that it's sale time.

One possible factor behind the exits could be the board dissatisfaction fingered in the case of Meyer. Of course, in the past six months, AMD's stock has posted a healthy 35 percent gain—compare it to Intel's 11 percent jump despite a string of record quarters. So what could AMD shareholders possibly be cranky about? NVIDIA is one possible answer.

NVIDIA is up over 150 percent in the past six months—a terrific run that parallels ARM's similar blast-off in this same timeframe. Jen-Hsuan's gamble with the launch of the Tegra line has paid off big time, and NVIDIA is reaping the rewards of the entire tech market's current infatuation with ARM. Meanwhile, as we pointed out in our coverage of Meyer's departure, AMD's answer to Tegra was the Imageon line—a great chip with a head-start against Tegra that AMD unfortunately sold to Qualcomm in order to keep itself afloat.

But ultimately, it's pointless to speculate about AMD's executive departures until we get more details. The fact that AMD blew its ARM opportunity while NVIDIA is blowing up could be a factor, but it could also come down to internal politics. Who knows.

What is clear is that while the departures amount to a shake-up, the sale thesis is still very weak.

x86 is not ARM

The idea that a larger x86 systems integrator like Dell might buy AMD to give it an edge is the kind of notion that could only have gotten any traction in the wake of ARM's rise. The pundits and analysts who propose such things are probably now seeing the x86 market through the distorting lens of the ARM ecosystem, and that's a mistake.

It's expensive to have your own in-house chip design team, so if you're going to do it then it had better make a whole lot of sense. In the case of the commodified ARM ecosystem, an in-house team that either tweaks the standard-issue ARM designs or does a new implementation from the ground up can enable an Apple or a Qualcomm to differentiate itself from a crowded field of competitors making mostly similar products from mostly identical microprocessor cores.

Contrast this to the x86 market, which isn't an "ecosystem" but is rather a single, giant integrated device manufacturer (Intel) and a much smaller, IP-only rival (AMD... and no, VIA isn't big enough to matter here). Given this dynamic, it's not at all clear why an x86 systems integrator would want to own its own in-house chip design team. Why not let AMD and Intel duke it out, and then pick from the best of each product cycle? Why take on all the risk of doing CPU and/or GPU design in competition with Intel? What business problem does this solve for anyone?

In other words, the decision to do ARM design in-house is a decision to try to differentiate yourself a bit from a crowded ecosystem; the decision to do x86 design in-house is a decision to compete with Intel on design and manufacturing prowess. The former makes sense, while the latter is a good way to earn yourself a really long string of money-losing quarters.

Finally, the Intel monopoly factor weighs against a sale of AMD.

As one pundit has sensibly pointed out, the purchase of AMD would amount to a declaration of war with Intel. Certainly the numerous patent cross-license agreements between the two rivals would come up for renegotiation in the event of a sale, but that licensing arrangement is not itself why Intel would oppose an AMD buy-out—rather, the threat of ending the cross-licensing pact is just the leverage that Intel would use to ensure that such a buy-out doesn't happen.

It's conventional wisdom at this point that Intel needs a viable, independent AMD in order to stay out of antitrust trouble in the US and Europe. And for once, conventional wisdom is probably right. If a Dell or an Apple were to buy AMD and then stop selling AMD chips to rival OEMs, Intel would be the only real x86 supplier left standing (again, ignoring VIA, which is absolutely minuscule). The moment a larger systems integrator announces a bid for AMD, Intel will have a talk with it and explain that if it purchases the chipmaker, then it will soon lose access to the x86 patents, in which case the GPU IP is all that will be left for them to develop. So unless the plan is to pair AMD's GPUs with an ARM core and use the resulting SoC to gain an edge in the ARM market, there seems to be no reason to buy the chipmaker.

So an AMD acquisition by the likes of Dell—or any other PC systems integrator—not only makes no sense, but Intel would surely never permit it to happen.

This isn't to say that AMD won't be purchased—some private equity group could buy it for whatever reason. Or, as I suggested above, if AMD becomes really cheap it might make sense for an ARM shop to buy them and then do an ARM CPU + ATI GPU fusion of the type that NVIDIA is working on with its Project Denver. But as a strategic acquisition that gives an x86 customer some sort of advantage over the rest of the x86 field (i.e., Intel's customers), it makes zero sense.