What happened

Shares of Advanced Micro Devices Inc. (NASDAQ:AMD) climbed 22.7% in September, according to data from S&P Global Market Intelligence, extending its 37% rise in August after multiple analysts piled on with positive comments on the chipmaker.

AMD's impressive run gained steam early last month, on Sept. 4, when analysts at Jefferies and Cowen each reiterated their buy-equivalent ratings and raised their respective price targets on AMD to $30 per share. Both firms noted that AMD should be able to take market share as rival Intel continues to struggle in resolving yield problems with its 10nm chip manufacturing process.

AMD Ryzen chip

IMAGE SOURCE: AMD.

So what

Then less than two weeks later, on Sept. 14, AMD continued to rally as analysts at Argus reiterated their buy rating and raised their per-share price target to $40. To justify their relative bullishness, Argus argued that AMD's Epyc line of products is helping the company take a larger piece of the server chip market.

Finally, on Sept. 21 -- and following an industry report asserting that Intel will probably undersupply the PC market amid a processor shortage in the coming quarters -- Jefferies weighed in once again by raising its price target on AMD from $30 to $36.

Now what

That said, AMD has also pulled back hard over the past week on subsequent reports that Intel may ramp up production of its 10-nm chips earlier than expected next year -- a development that would undoubtedly crimp AMD's ability to take market share by filling that gap.

Perhaps it should have come as no surprise, then, when analysts at RBC mused shortly thereafter that AMD remains a "high-risk/high-reward" stock with outsize volatility until the market receives more clarity on its competitive situation with Intel. Until then, with shares still up 150% so far in 2018, I'm content watching AMD's story play out from the sidelines.

Steve Symington has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Jefferies Financial Group Inc. The Motley Fool has a disclosure policy.