Nvidia took the chip from its DGX Spark, put it in a Windows laptop, and called it RTX Spark. On paper, it’s the local AI laptop I’ve wanted for years: up to 128GB of unified memory, CUDA, and a chip that was already here under a different name. I’ve spent the past week running models on a Lenovo Yoga 9n 2-in-1 with 64GB, along with games and other tasks.