unsloth Qwen3.8-Flash-Next-UD-IQ4_XS on 5x RTX PRO 4000 Blackwell 4x 16, stuck at 43 tps

Hi everyone,

I’m running Unsloth’s Qwen3.8-Flash-Next UD-IQ4\_XS locally through Unsloth Studio on Windows. No matter what I change in settings, I can’t seem to get beyond roughly 43 tokens/s during generation with longer prompts.

My hardware:

5× NVIDIA RTX PRO 4000 Blackwell, 24 GB each

All five GPUs running at PCIe 4.0 ×16, in TCC mode

AMD Ryzen Threadripper PRO 3945WX, 12 cores / 24 threads

GIGABYTE MC62-G40-00

128 GB RAM (DDR4 2666)

NVIDIA driver 596.36

I’m using a 65,536-token context window, one parallel slot, and Flash Attention. GPU utilization during generation is low, with power consumption well below the cards’ limits.

Am i missing an important configuration setting, does someone has a similar setup and gets more tokens/s?

thanks in advance