No, didn't see the upgrade, I saw that the shares jumped on yet more rumors (This time on Intel picking up AMD graphics tech licensing) - which will likely be true, IMO. Let's face it, if "Intel HD Graphics/Iris" is the result of the NVIDIA 5-year deal.. well, ya, a no-brainer for Intel and a likely proposition. On the flip side of that coin is that Intel chips will be even more competative at lower prices since they won't be paying the type of royalties they currently do to NVIDIA.
The stock looks, to me, to be overextended already. It's way above the 50 day moving avg and is having trouble holding the speculation spikes. Some of the other technical indicators are indicating over extension as well. Everything is already baked into the stock, I would be worried for "buy the rumor, sell the news". About the only thing not baked in is a full takeover of the company (Which could realistically happen - what if that is really the Intel deal?)
Back to the upgrade (just read up on it) - it simply got upgraded because of the buying frenzy, bittersweet news in the datacenter and more "rumors" - I get it, but if you were not already 'in',
now is a risky time to try to make ROI.... what that usually means is that bundlers and pro traders are looking for the "last suckers" to pump the price 'before the fall'.
Looking at the stock, I believe the stock is truly worth $6-8 as per the previous support level. If all goes OK, then that level may rise slowly over time but if there are any hiccups (No matter if it's supply issues, technical issues, lackluster performance, etc) we may see the company sold or a hostile takeover.
Nobody seems to be factoring in Intel. They can easily drop their prices to be more competitive(and still be profitable) and they have new chips right around the corner which could offset much of AMD's recent successes in both the cost and performance arena. Also, Qualcomm is going to be entering the OEM laptop and desktop market in 3-4Q 2017 which will directly compete with AMD, perhaps (If not on performance, certainly on price).
https://www.engadget.com/2016/12/07/windows-10-snapdragon-arm/
https://www.qualcomm.com/news/snapdragon/2016/12/07/windows-10-powered-snapdragon
I'm no expert, but definitely lock your gains in soon and re-buy after, if advantageous. December 13th?