Coding Horizon

Qwen 3.8 flash passed 125 tok/s with this speed trick

Every figure, name, version and benchmark the finished picture puts on screen, chased to a primary source. Checked 22 September 2026.

The model

Claim Value Source
Total parameters 125B Qwen/Qwen3.8-Flash-Next model card — “Number of Parameters: 125B with 6B activated, plus 51B n-gram embedding and 4B MTP”
Active per token 6B same line
The separate lookup table 51B n-gram embedding table, 128 shards, held in BF16 same card; shard count from primitive-ai/Qwen3.8-Flash-Next-NVFP4
Experts 512 total, 11 activated per token, 48 layers Qwen model card
Architecture Gated DeltaNet plus Qwen Sparse Attention, mixture of experts Qwen model card
Context 262,144 native, extensible to 1,000,000 Qwen model card
MTP “MTP: 1 layer, trained with multi-steps” Qwen model card
Release date 26 August 2026 BenchLM comparison, specification table
A hosted flash service exists beside the weights “the official Qwen API service is provided by Qwen Cloud. In particular, Qwen3.8-Flash is the official version based on Qwen3.8-Flash-Next” Qwen model card, opening callout

The script’s “about six billion active per token” and “a separate lookup table adds capacity too, so the active count isn’t the download size” are both exactly what the card says. The card’s own model size badge reads 180B params, which is the 125B plus the 51B table plus the 4B MTP head, and is why the download is far larger than 125B implies.

The benchmark figures the video states

Benchmark Qwen3.8 Flash Next Qwen3.8 27B DeepSeek V4 Flash 0731 Source
SWE bench Pro 62.5 61.7 52.6 Flash Next card, 27B card, BenchLM
DeepSWE 1.1 58.7 42.2 54.4 Flash Next card, 27B card, BenchLM
NL2Repo (repository generation) 48.1 not published 54.2 BenchLM

DeepSeek, for the comparison the video keeps open

Claim Value Source
V4 Flash 0731 release 31 July 2026, 284B parameters DeepSeek V4 Flash official release, BenchLM specification table
V4 Flash documented context 1M BenchLM specification table
V4.1 Flash release 10 September 2026, 552B parameters V4.1 Flash against V4 Flash
V4.1 Flash DeepSWE 1.1 74.2 same
V4.1 Flash native context 1M same

Worth stating plainly, because the video’s own argument rests on it. V4.1 Flash scores 74.2 on DeepSWE 1.1 against Flash Next’s 58.7. The narration never claims Flash Next is the best local coding model; it says the older chart does not settle a whole repository build, and that another local model is worth keeping. The picture is built to agree with that and never draws Flash Next as an outright winner.

Installing it

Claim Value Source
Unsloth Desktop runs on macOS, Windows and Linux yes Unsloth: Qwen3.8 Flash Next, how to run locally
The GGUF release unsloth/Qwen3.8-Flash-Next-GGUF the repository
Quants and sizes UD-IQ1_S 72.5 GB · UD-IQ1_M 74.5 GB · UD-Q2_K_XL 78.9 GB · UD-IQ3_XXS 82 GB · UD-Q3_K_XL 90 GB · UD-IQ4_XS 93.7 GB · UD-Q4_K_XL 111.3 GB · UD-Q5_K_XL 158 GB · UD-Q6_K_XL 169 GB · Q8_0 192 GB · BF16 354 GB Unsloth docs and the GGUF repository’s hardware compatibility table
File size is not the whole requirement “You will need at least 75 GB of RAM or unified memory to run the model”, and 1 to 2 GB extra headroom for MTP Unsloth docs
Recommended generation settings thinking: temperature 1.0, top-p 0.95, top-k 20 · instruct: temperature 0.7, top-p 0.80, top-k 20 · context up to 262,144 Unsloth docs
1 bit is 79% smaller than BF16 and retains a top-1 accuracy of 80% stated Unsloth docs

MTP, and what switching it on does

Claim Value Source
Unsloth configures speculative decoding automatically “Unsloth Studio automatically sets the ideal MTP settings optimized for your specific hardware”; MTP enabled by default in Unsloth Desktop Unsloth MTP guide
The advanced settings expose it MTP / Ngram speculative decoding and the number of draft tokens, in the right sidebar Unsloth MTP guide
Do not start at the maximum draft length “The best starting point is --spec-draft-n-max 2, however, do not assume 2 is optimal … Try any value from 1 through 6” Unsloth MTP guide
What Unsloth measures for this model 1.3 to 1.7x faster, “170 tokens/s on 1x RTX 6000 PRO GPU compared to the 100 token baseline” Unsloth docs
A draft mechanism proposes, the main model verifies that is what multi token prediction is; the model ships an MTP layer for it Qwen model card, Unsloth MTP guide

The 142 token recipe

The page the narration names is primitive-ai/Qwen3.8-Flash-Next-mixed-NVFP4-FP8, and its own formats line reads NVFP4 + FP8 + BF16, which is exactly the mix the script describes. primitive publishes a plain NVFP4 build beside it, and that one is NVFP4 experts with a BF16 tail and no FP8 at all; both report the same speculative comparison.

Claim Value
Without speculation 91.2 tokens per second
With MTP at three speculative tokens 142.6 tokens per second, reported as +56%
The speculative configuration {"method":"mtp","num_speculative_tokens":3}
The docker image vllm/vllm-openai:qwen38-flash-next
The launch command’s own flags --distributed-executor-backend mp, --gpu-memory-utilization 0.92, --max-model-len 32768 --max-num-seqs 36, with VLLM_PLE_CPU_OFFLOAD=1, VLLM_PLE_OFFLOAD_READY_TIMEOUT=1800 and VLLM_GDN_DECODE_KERNEL=triton
The startup overlays connector_mrv2.py, which fixes a startup race, and worker_image_disk.py for disk backed table offloading
The hardware one RTX PRO 6000 Blackwell, 96 GB, with about 100 GB of host RAM
How it was measured single stream, real prompts, thinking enabled, output tokens over wall time, prefix cache free, distinct seeds per run
What is quantised to what routed experts, 120.8B, NVFP4 group 16 · QSA attention, 12 layers, FP8 E4M3 per channel · GDN linear attention, 36 layers, FP8 E4M3 per channel · the n gram table and everything else BF16
The compressed lookup table recipe a separate PLE-quant repository: FP8 per row 49 GB, INT4 group 16 32 GB, NVFP4 style e2m1 group 16 28.8 GB, against about 95 GB

142.6 divided by 91.2 is 1.564, so “about 56 percent faster” is right.

One figure on that page that is NOT the one the video states. The card’s own header badges read 84.4 tok/s @ 1 and 526 tok/s @ 32, which are a different measurement from the 91.2 against 142.6 in its body: a different prompt set at two concurrencies rather than the speculation on and off comparison. The video quotes the body’s pair and draws only that pair, and neither badge figure appears anywhere on screen.

Arithmetic the video states

Not checked