Move over Nvidia, there's a new chip champion in town. Memory-chip maker Micron Technology has taken its title as the primary beneficiary of the huge wave of spending on artificial-intelligence infrastructure. Now the question is whether it can keep it.

Micron's earnings figures were just as mind-blowing as Nvidia's most impressive quarters. Managing to quadruple revenue with gross margins of 85% is a rare feat. And Micron insists it's not a one-off, with the memory-chip shortage set to last at least another 18 months.

Where once commentators spoke of an "Nvidia tax," it has been replaced for large tech companies such as Apple with a "Micron tax" -- or at least a memory toll, as Micron's South Korean rivals are reaping similar rewards. U.S. investors wanting to spread their bets on the memory boom will soon have the option of also investing in SK Hynix as it plans to list American depositary receipts next month.

But Nvidia also provides a cautionary tale for Micron shareholders. While still the leading AI chip supplier, Nvidia's stock has been an underperformer this year. A flood of new AI processors is disrupting what had once been a quasi-monopoly and the competition shows no signs of slowing -- just this week ChatGPT-developer OpenAI unveiled its custom AI chip designed with Broadcom, while Qualcomm announced supply deals with Microsoft and Meta Platforms.

Will Big Tech also seek to undermine Micron and its South Korean peers? Micron is taking pre-emptive action by locking in long-term supply deals with fixed price ranges, hoping to keep its big customers on side. But companies such as Microsoft and Google-parent Alphabet are under stock market pressure to show they can control their AI spending, which means at the very least they will be investigating ways to reduce the amount they are paying to Micron.

Micron has taken the AI stock crown. But as Nvidia has found, being on top makes you a target.