IBM’s mainframe chip collab, NVIDIA’s Poolside deal & Ox Alpha’s reveal

On episode 122 of Mixture of Experts, hosts Tim Hwang and Aili McConnon are joined by Gabe Goodhart, Ash Minhas, Skyler Speakman to talk hot chips, mystery models, and major money moves. We open with IBM's Hot Chips conference reveal of its dual-architecture mainframe processor built with Arm that lets IBM Z and LinuxONE systems run Arm-native Linux workloads right alongside z/OS. We break down what this means for enterprises balancing legacy reliability with the fast-moving Arm software ecosystem. Next, we talk about NVIDIA and its $6 billion deal with Poolside to license its "Model Factory" software and hire over 100 of its staff. We unpack why NVIDIA keeps using this licensing structure instead of straightforward acquisitions, and how it fits alongside its earlier deals. Finally, we dig into Ox Alpha, the anonymous "stealth model" that appeared on OpenRouter and was ultimately confirmed to be Z.ai’s open-source GLM-5.3-Flash, an efficient large language model built with sparse and linear attention techniques. But is the stealth launch the future of model releases? 00:00 – Intro 1:18 - NVIDIA’s $6 billion Poolside deal 13:10 - IBM’s new mainframe processor 24:30 - Ox Alpha, Z.ai’s newest model All that and more on this week’s Mixture of Experts. "The opinions expressed in this podcast are solely those of the participants and do not necessarily reflect the views of IBM or any other organization or entity. AI tools may be used to transcribe this episode and support selected stages of the production process. All AI-assisted content is reviewed by the production team before publication."