Musk says Tesla halved AI5 chip memory to 72GB and cut AI6 by a third for Optimus

Elon Musk posted on X on October 1, 2026 that Tesla had cut the RAM on its AI5 chip in half, to 72GB of LPDDR5, and reduced AI6 to 144GB of LPDDR6. He said the change was needed to reach enough volume for Optimus production and would have a 'negligible effect' on robot performance because memory bandwidth was held constant. The report came after Micron suggested humanoid robots could need more memory than current designs carry. Tesla has not published a filing on the change, so the figures rest on Musk's post.

• AI5: now 72GB LPDDR5 (per Musk's X post)
• AI6: now 144GB LPDDR6, cut by about a third (per the same report)
• Musk: effect on Optimus performance 'negligible'; no Tesla filing or release yet