New Delhi, Sept. 9 -- Chalk up another in the seemingly endless string of artificial-intelligence chip deals. Qualcomm has signed up Amazon.com as a customer for its processors but the size and structure of the deal shows it's still far from being a major threat to Nvidia.

Nvidia shares were down 0.6% at $224.55 in Wednesday's premarket. That was adding to a 2% fall the previous day.

Some shareholders might be concerned that Qualcomm's announcement Tuesday that it would provide work on custom chips with Amazon will eat into Nvidia's business with the e-commerce giant. But it's worth taking a closer look at the deal.

Firstly, take the size. The headline figure for the Qualcomm-Amazon deal was for up to $60 billion in potential purchases...