Qwen3.8 27B Swift-1.5

User compares Qwen3.8 27B Q8 with q8_0 KV cache at 262k context on two RTX 5090s across two systems. On a 9950X with 64GB DDR5 6000, infill was 2500-3000 t/s and output 100-150 t/s. After moving the cards to a Proxmox VM on a 7402P with 256GB DDR4 3200 ECC, infill rose to 3800 t/s but output fell to around 60 t/s. Setup is Unsloth Studio with Q8 weights and q8_0 KV cache, two 5090s passed through to the VM. User asks what could cause the output drop and mentions memory bandwidth tests showing 90-120 GB/s on the 4-CCD CPU versus a theoretical 204 GB/s.