Goldman Sachs has had a sell rating on shares of Advanced Micro Devices Inc. (AMD) even as the stock rallied more than 86% this year. Now, the firm is conceding that its outlook on AMD may have been too pessimistic.

Goldman increased its rating on AMD to neutral from buy, saying it expects the chipmaker to snag significant market share from competitors in the next two years, especially as Intel Corp. (INTC) has struggled to make a competitive chip. Its price target increased to $21 from $13.25, a 10% upside to Thursday’s close.

"We find it increasingly harder to argue our prior bear thesis—even following the recent stock price move—given Intel's struggles with 10nm process technology," Goldman Sachs analyst Toshiya Hari said in a note to clients. "The delay in Intel’s new products will allow AMD to gain share in not only client (i.e. desktop PC, notebook PC) CPUs, but also in the lucrative server CPU market."

So far this year, AMD shares are up 16% in the past month, and up 58% in the past 52 weeks. So far this year, it’s proven to be the second-best performing stock in the S&P 500.

Intel Downgraded

Goldman Sachs also downgraded shares of Intel, joining a growing number of Wall Street analysts growing cautious on the technology firm as it grapples with delays in the production of its next-generation chip. (See also: Goldman Says Sell Intel on Next Gen Chip Delays.)

Goldman cut its rating on Intel to sell from neutral, with a price target lowered to $44 from $49, a roughly 12% downside to Thursday’s closing price.

"We believe Intel's struggles will provide a reason for customers (PC OEMs, server OEMs, Cloud Service Providers, etc.) to adopt, or at least investigate, AMD's product," Hari said.