Musk: Grok 4.8 ditches JAX/SGLang for from-scratch C/C++ stack, now in RL
tetsuoai · x · 2026-11-10
Elon Musk says xAI dumped JAX/SGLang and rewrote its entire RL and inference stack from scratch in C/C++. Pre-training for Grok 4.8 is done, SFT data was heavily cleaned, and the model is now in RL with evals climbing. A soft rollout to Bot users is planned later this week. He claims 4.8 will bear no resemblance to 4.7 and, with foundations built right this time, could evolve into something special.
Related event: Musk says xAI rewrote Grok training stack in C/C++, dropping JAX and SGLang(3 posts)→
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