Fitting 4x RTX 3090 in one case: which PCIe 4.0 risers actually work
infectiousstupidity · reddit · 2026-11-03
A Redditor runs 4x RTX 3090 (24GB) in a Fractal North XL Mesh for vLLM inference (qwen3.8-27B / Strata QFN IQ3S) at x8/x8/x4/x4 with GPUs capped at 250W. They ask for proven PCIe 4.0 risers at 50-75cm: ADT-Link vs generic AliExpress, whether OCuLink/MCIO beats ribbon cables, cheap M.2-to-x16 options, and gotchas around PCIe errors, signal integrity and Linux P2P.
More from Infra
- FLAMIA: MXFP8 microscaling attention kernel for fast, causally-safe training on Blackwell — yresearch · 2026-11-03
- 2,500+ GW of power projects stuck in grid queues as $200B flows into energy tech — ingliguori · 2026-11-03
- Build a Media Agent workshop: CPU-based agent calling GPU tools on demand — Al_Grigor · 2026-11-03
- Factory rebuilt its Droid coding agent to run inside customers' own clouds, plans to open source the compute layer — AI Engineer · 2026-11-03
- DeepSeek V5 reportedly to be pretrained on Huawei Ascend chips, Ascend 960DT due Q1 2027 — teortaxesTex · 2026-11-03
- Korean HBM smuggled into China: The Information investigates — AccBalanced · 2026-11-03