Strix Halo teaser: 88 GB Qwen3.8-Flash-Next (512 experts) at 45–50 tok/s on a Radeon 8060S — what we've been cooking in our llama.cpp fork

#70
by Fbrbiasi - opened

We've been quietly grinding on the Ryzen AI Max+ 395 (Radeon 8060S, gfx1151, 128 GB unified) for a few weeks. Here's a peek before the full write-up.

The model: Qwen3.8-Flash-Next. 177B MoE with ~3B active, 512 experts, top-10, hybrid Gated DeltaNet + sparse attention. We run unsloth's UD-IQ4_XS GGUF (87 GiB).

What it does on one APU, measured end to end with real ~8.5K and ~34K-token prompts:

  • 45–50 tok/s decode with MTP speculative decoding (draft 3, 66–70% acceptance)
  • 27–28 tok/s without speculation
  • 1,200 tok/s prefill, even on 34K-token prompts (1,100 with the MTP head loaded)
  • For scale: upstream llama.cpp on the same machine, with the same GGUF and prompts, does ~220–320 tok/s prefill and 14–19 tok/s decode (its build has no MTP for this architecture)
  • Running daily as the backend of our local agent setup, with conversations of 50K+ tokens

What's under the hood (a few highlights):

Next on the bench: the larger UD-Q4_K_XL quant (111 GB), which cuts unsloth's measured KLD from 0.084 to 0.047. We want to see what that quality costs in speed and memory on a 128 GB machine.

Also coming: our sub-2-bit ternary formats (TQ1_1 / TQ2_1). A 27B model in 5.5–6.7 GB, running on a 6 GB GPU from 2016 or on an iGPU with no dedicated card.

All numbers are from a single PX13 laptop with strix halo
on AC power: engine-reported, median of warm runs, the same prompts for every engine, temperature 0. Full methodology, the op-by-op ROCm vs Vulkan breakdown, and quality numbers (KLD vs the reference quant) are coming in the proper post.

It will be available on 10/09/26 https://github.com/ftoleedo

What would you want to see benchmarked on Strix Halo? Drop your model and quant below.

flashnext-strixhalo-20261002-v3

Since the model's context is really compact per token, so I'd like to see a bit higher memory utilization, like 100Gb. Currently running Unsloth UD-Q4_K_XL, fits pretty tight, but slower that your numbers here.

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flashnext-strixhalo-20261001
my last tests

Fbrbiasi changed discussion title from Strix Halo teaser: 88 GB Qwen3.8-Flash-Next (512 experts) at 42–44 tok/s on a Radeon 8060S — what we've been cooking in our llama.cpp fork to Strix Halo teaser: 88 GB Qwen3.8-Flash-Next (512 experts) at 45–50 tok/s on a Radeon 8060S — what we've been cooking in our llama.cpp fork

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