Shares of Advanced Micro Devices Inc. AMD, -2.11% were having their best day in over 40 years, after the company announced a new licensing deal to a chip joint venture in China and reported better-than-expected quarterly results and outlook. The stock rocketed 36% in morning trade, the biggest percentage gain since it shot up 63% way back on Jan. 29, 1975. Volume hit 66 million shares within 90 minutes after the open, already about five times the full-day average. The stock was both the biggest gainer and most active on the Nasdaq exchange. Analyst Ian Ing at MKM Partners upgraded AMD to buy from neutral, and raised its stock price target to $4 from $2.90, saying the new China JV could become the best challenge yet to Intel Corp.'s INTC, -0.85% server dominance. It has now surged 56% over the past 12 months, putting it on track to close at the highest level since Sept. 29, 2014. In comparison, Intel shares have lost 3.4% over the past year and the S&P 500 has slipped 1.2%.