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Google reportedly developing 6D Torus for future TPUs, enhancing interconnects

Google is reportedly evolving its Tensor Processing Unit (TPU) interconnect topology, moving from a 3D Torus to a 6D Torus for future models like TPUv9t. This new architecture, detailed by SemiAnalysis, aims to reduce communication hops and increase bisection bandwidth, though it will require more optics. Google has also introduced the Boardfly topology with TPUv8i for inference-specific chips, while maintaining the 3D Torus for training-focused chips like TPUv8t. AI

IMPACT This evolution in TPU interconnects could significantly boost training and inference performance for future AI models.

RANK_REASON The cluster details rumored architectural changes to Google's TPU interconnect topology, which is a technical research and development topic.

Read on X — SemiAnalysis →

AI-generated summary · Google Gemini · from 8 sources. How we write summaries →

Google reportedly developing 6D Torus for future TPUs, enhancing interconnects

COVERAGE [8]

  1. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    To learn more about ICI networking topology, please refer to our networking model (8/8) https://t.co/kqt0IiSiFi

    To learn more about ICI networking topology, please refer to our networking model (8/8) https://t.co/kqt0IiSiFi

  2. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    For a fixed chip count the diameter collapses. For a 4,096 chip cluster, the worst-case is 24 hops with a 16×16×16 3D torus, but 12 hops with a 4⁶ 6D Torus. Thi

    For a fixed chip count the diameter collapses. For a 4,096 chip cluster, the worst-case is 24 hops with a 16×16×16 3D torus, but 12 hops with a 4⁶ 6D Torus. This is not the onlye benefit as bisection bandwidth multiplies. However, this all comes at the cost of far more optics

  3. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    Inside the rack, chips wire up exactly as in today's 3D torus, over short copper. Each chip's other 6 neighbors sit at the same position in the six adjacent rac

    Inside the rack, chips wire up exactly as in today's 3D torus, over short copper. Each chip's other 6 neighbors sit at the same position in the six adjacent racks, and the rack grid itself forms a second 3D torus, stitched together in optics. (6/8)

  4. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    A 6D torus doesn't add diagonals, it adds three entirely new dimensions, doubling each chip's ICI links from 6 to 12. It can be visually represented by a cube o

    A 6D torus doesn't add diagonals, it adds three entirely new dimensions, doubling each chip's ICI links from 6 to 12. It can be visually represented by a cube of cubes: each small cube is a TPU, each 3D-torus block is a rack. (5/8) https://t.co/5eVR8WBOaX

  5. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    In a 3D torus, each TPU talks to 6 neighbors (±X, ±Y, ±Z). Picture a cube of chips: every chip links to the ones beside it, and chips on an edge wrap around to

    In a 3D torus, each TPU talks to 6 neighbors (±X, ±Y, ±Z). Picture a cube of chips: every chip links to the ones beside it, and chips on an edge wrap around to the opposite edge. That wraparound is what makes it a torus rather than a mesh, and it's what the OCS layer provides. ht…

  6. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    Recent rumors hinted that Google will likely maintain this dual track with TPUv9, with the inference-specialized chip (TPUv9i) iterating to a newer version of B

    Recent rumors hinted that Google will likely maintain this dual track with TPUv9, with the inference-specialized chip (TPUv9i) iterating to a newer version of Boardfly and the training-specialized TPU (TPUv9t) introducing an evolution of 3D Torus called 6D Torus. (3/8)

  7. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    With Ironwood (TPUv7), Google kept the 3D Torus of 64-chip cubes, scaled via OCS to 9,216 interconnected chips. Earlier this year during Google Cloud Next 2026,

    With Ironwood (TPUv7), Google kept the 3D Torus of 64-chip cubes, scaled via OCS to 9,216 interconnected chips. Earlier this year during Google Cloud Next 2026, the firm unveiled TPUv8t and TPUv8i, with TPUv8i introducing a new ICI topology called Boardfly and TPUv8t sticking to …

  8. X — SemiAnalysis TIER_1 English(EN) · SemiAnalysis_ ·

    Over the years, Google has been improving its original 2D Torus Inter-Chip-Interconnect (ICI) network topology introduced with TPUv2, later extended to a 3D Tor

    Over the years, Google has been improving its original 2D Torus Inter-Chip-Interconnect (ICI) network topology introduced with TPUv2, later extended to a 3D Torus starting with TPUv4 and v5p. (1/8)🧵 https://t.co/rtU0TkUzZw