>What prevents AMD from turning it around on them?

Matt's telling is a little facetious, so the exact negotiation probably didn't go like that. More importantly, OpenAI has better options. If they want to pay AMD cash for chips, they could do that without also giving up their equity. The same can't be said for AMD. They're the second choice when it comes to GPUs, and they're desperate for market share, so they're willing to cut deals like this. Without this deal OpenAI probably would have bought Nvidia chips with cash.