Go back to March and the difference is even more stark. AMD was up 50% from January then. But after it announced its first quarter numbers, in April - a nasty $580 million loss related to its split from Global Foundries - it began a steady fall from over $8 to under $7/share.
Regular followers of both companies know this is part of the regular ebb-and-flow of the two stocks. AMD rises near the end of a product cycle, peaks around the time Intel announces its new line, recovers a bit after its own announcement, then goes back into the tank. Over the last five years AMD has lost half its value, while INTC is up 20%.
The news today is AMD's alternative to Intel's Ivy Bridge, called Trinity. The chip is a low-end alternative, and priced like it, better than previous editions, not as good as the Intel alternative, and doomed to low-end devices called "ultrathin notebooks," as opposed to Intel-based Ultrabooks.
Comparing the two lines is more complicated than ever, but reveals some opportunities. The AMD chip turns out to be better for gamers than the Intel chip, with faster graphics processing, but for regular office functions it's not very good at all.
What this tells me is that there's a disconnect between what AMD is shipping and what it's being shipped in. Game-first people are actually a big market (my son is in that market) and are accustomed to paying up for performance. But the systems they buy have to be built with gaming in mind - not as gaming systems (they are PCs after all), but with peripherals and plugs gamers will crave.
That doesn't seem to have happened in this case. Which means we have another case of AMD fail and can see another fall in the stock.
Disclosure: I am long INTC.