American graphics card manufacturer Nvidia’s stock price tumbled in after-hours trading on Thursday because the revenue outlook for Q2 has fallen short of expectations.

Quarterly growth from Q4 2021 to Q1 2022 was strong, with an 8% increase in revenue to $8.98 billion and a 3% increase in earnings per share to $1.36. It also stated it would continue a $15 billion share buyback program through the end of 2023, according to the filing to the United States Securities and Exchange Commission (SEC).

However, the Q2 outlook is much less promising and projects revenue will be $8.1 billion, which is 4% lower than expected.

The disappointing guidance didn’t impress investors in after-hours trading on Thursday with Nvidia (NVDA) shares down 7% to $157.8. NVDA is down nearly 50% over the year, mirroring the poor performance of tech stocks across the market.

The tech firm saw a drop in sales of its Cryptocurrency Mining Processor (CMP) in Q1 to “nominal” levels compared to $155 million a year ago. The filing does not specify exact revenues on CMPs, but revenues have been falling since last year.

Nvidia saw a 33% shortfall in expected CMP revenues in Q2 last year to $266 million, followed by $105 million in Q3 and then $24 million in Q4. That’s now fallen again.

Nvidia revised its revenue expectations for Q2 in the report down to $8.1 billion “plus or minus 2%” due to “Russia and the COVID lockdowns in China.” 

Those two factors alone could drive revenues down as much as $500 million as the report says.

Related: GPU prices are still on a decline: Is Bitcoin’s sorrow gamers’ joy?

The Santa Clara-based company’s CMPs can be used to mine Bitcoin (BTC), Ether (ETH) and a range of other cryptocurrencies. Its graphics cards, designed for gaming, can also be used to mine cryptocurrency unless limited.

Supplies of CMPs are extremely scarce even on secondary markets, possibly causing sales to be so low. A new CMP 170HX, the highest-rated model to date, cost $4,700 when they were launched last October.

On May 6, Nvidia was forced to pay $5.5 million to the SEC to settle a case in which it was accused of failing to disclose how much of its revenue came from crypto mining in 2018. The announcement spooked investors, who sold NVDA down 6% on May 9, the next trading day.