Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Advanced Micro Devices, Inc. (NASDAQ:AMD) plunged 12% Wednesday, after the company turned in decent fourth-quarter results but offered disappointing forward guidance.

So what: Fourth-quarter 2013 sales rose 38% year over year to $1.59 billion, compared with analysts' estimates which called for sales of just $1.54 billion. Despite the revenue beat, however, AMD still only recorded inline adjusted net income of $45 million, or $0.06 per share. Gross margin also fell by one percentage point to 35% as AMD's low-margin console gaming business continued to forge ahead.

In addition, AMD stated that first-quarter 2014 revenue is expected to decrease 16%, plus or minus 3%, compared with an 11% fall forecast by analysts. Meanwhile, gross margin is expected to remain depressed at around 35%.

Now what: Shares of AMD don't look particularly compelling to me, trading at around 37 times next year's estimated sales -- and keep in mind those estimates are likely to fall once analysts have time to fully digest today's news.

However, I think investors would be wise to at least add AMD to their watchlists, considering it is faring significantly better than it was in the same year-ago quarter, when the company recorded a harrowing adjusted $102 million net loss. AMD still has plenty of work to do -- most notably in chipping away at its massive $2 billion long-term debt pile -- but could stand to reward patient long-term investors if it can continue marching toward sustained long-term profitability.