Zed's version 0.121 update introduces significant performance improvements, thanks to feedback from streamer Theo Browne and subsequent optimizations by the Zed team. Initially, the team discovered janky scrolling on Theo's M2 MacBook, unlike their M1s, which led them to investigate and modify the rendering logic. By switching from composited to direct mode and adjusting synchronization in the MetalRenderer, they improved the app's responsiveness. However, this change led to memory corruption issues, prompting the team to implement a triple-buffering system to prevent race conditions. Further enhancements included the use of CADisplayLink to maintain a consistent refresh rate, ensuring smooth cursor movement and responsiveness by temporarily disabling ProMotion. Despite initial challenges, including reports of capped frame rates, the team resolved these by adjusting synchronization methods and employing CVDisplayLink, leading to a stable 120 FPS and smoother overall performance. This iterative process exemplifies Zed's commitment to learning and optimizing based on user feedback, resulting in a much-improved user experience with the latest release.