Barclays is saying the cryptocurrency mining-driven demand for AMD’s graphics cards will not last and is telling investors to avoid the chipmaker’s shares.

The bank’s semiconductor analyst Blayne Curtis reiterated his underweight rating and his $9 price target for AMD, representing 33 percent downside from Monday’s close.

“We are revisiting AMD’s last earnings release with an analysis of the ethereum tailwind, which now appears to be the source of the better revenue in June/Sept [guidance], and why investors should place very little value on this earnings stream,” Curtis wrote in a note to clients Tuesday. “We believe estimates could be too high next year should this ethereum tailwind dry up.”

Cryptocurrency miners use graphics cards from AMD and Nvidia to “mine” new coins, which can then be sold or held for future appreciation. AMD traditionally has a better reputation for mining cryptocurrencies such as Ethereum, according to Wall Street.

Ethereum cryptocurrency is up more than 3,300 percent year to date through Tuesday, according to data from industry website CoinDesk.

The analyst cited how ex-cryptocurrency mining market demand, AMD has lost market share to Nvidia in the gaming market, according to data from Steam, a digital PC game store. In addition, he estimates due to high graphics card prices in the secondary market it is now not profitable to mine ethereum.

“We still believe AMD is seeing little traction with it server chip (Epyc) and this likely crypto headwind only bolsters our underweight thesis,” Curtis wrote.

The company’s shares are one of the market’s best performing equities in the past year with the stock up nearly 100 percent in the past 12 months through midday Tuesday compared with the S&P 500’s 14 percent return. That performance ranks No. 3 in the entire S&P 500, according to FactSet.

The chipmaker reported better-than-expected second-quarter earnings and guidance last month.

AMD did not immediately respond to a request comment.

— CNBC’s Michael Bloom contributed to this story.