Qwen3.8 27B

User benchmarks Qwen3.8-27B Q4_K_M across two RTX 3090s in llama.cpp, with a 4096-token prompt and TG128 generation. The layer split reached 1,616 t/s prompt and 40.56 t/s generation, against 1,235 / 39.16 t/s on a single GPU. Setup is llama.cpp build 10775 with F16 KV cache, -ngl 999, flash attention on, no speculative decoding and a single request; the 16.46 GB file fits on one 24 GB card. Both cards ran at PCIe Gen2 x1 with no P2P. Tensor split was slower: built-in AllReduce gave 140 t/s prompt and 41.10 t/s generation, NCCL 169 t/s and 31.25 t/s. The user concludes layer split was clearly more practical in both speed and latency on this machine.