amd recently made some sales of subsidiary asian company s and sold licensing agreements which together came to about $600m which near enough cancelled out last years losses, this had a big boost on the value of stocks as far as im aware (compared to the start of the year)
And now with zen polaris and also the deal with the consoles, i cant see stock prices plummeting too far. although i dont think they will be at nvidia lvls any time soon, i would imagine they should climb to about $10 or so reasonably quickly. but i dont imagine they will get above $20 unless the market share on gpu's dramatically changes on the release of polaris. And if that did happen it would probably bring the market values of the stocks back in line to when they were more competitive, which would still only be about 50% of the cost of a nvidia share