AI article
PCIe 4.0 x8/x8 vs x16/x16 for Dual GPUs: Does Bandwidth Choke Local LLM Tensor Parallelism?
Community description: An engineering audit on bus bifurcation, NCCL AllReduce synchronization bubbles, and 70B token generation velocity.
Dev.to | Oct 12, 2026 | abdul rahman
Automated excerpt
PCIe 4. 0 x16 Configuration: Aggregates 16 lanes, providing approximately 31. 5 GB/s unidirectional (63 GB/s bidirectional full-duplex). Does PCIe 4. 0 x8/x8 choke dual-GPU local LLM inference? A PCIe 4. 0 x16 slot provides approximately 31. 5 GB/s of theoretical unidirectional bandwidth (63 GB/s bidirectional).
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