5090 dflash results - can you share details?

#21
by csabakecskemeti - opened

First of all, thanks for shipping this model, and especially for releasing the DFlash drafter alongside it โ€” it's great to see speculative decoding supported out of the box.
I'm trying to reproduce the RTX 5090 row from the model card:

GPU Baseline (tok/s) With DFlash (tok/s) Speedup
Nvidia RTX 5090 74.9 233.4 3.1x

I'm peaking at 137 tok/s, using your own GGUFs for both the target and the drafter, so I don't think this is a conversion or quantization issue on my side.

Setup: RTX 5090, llama.cpp master d2f83055d, CUDA build with CMAKE_CUDA_ARCHITECTURES=120, Release. muse-glimmer-30B-kquant-17gb.gguf + dflash-kquant.gguf, both from this repo. 512 tokens generated, greedy, batch 1, 71-token prompt.

claimed mine
Baseline 74.9 tok/s 82.91 tok/s
With DFlash 233.4 tok/s 137.14 tok/s
Speedup 3.1x 1.65x

llama-server
-m muse-glimmer-30B-kquant-17gb.gguf
-md dflash-kquant.gguf
--spec-type draft-dflash --spec-draft-n-max 15
-ngl 99 -ngld 99 -fa on -c 8192 -np 1 --temp 0 --top-k 1 --jinja

Meta Inc. org

Could you try with https://github.com/ggml-org/llama.cpp/pull/26842? It's an important optimization, we haven't managed to merge it in time but it's work in progress (as you can see from the PR description)

Inluding the optimization improved my results but still far form the claimed level

Run tok/s Acceptance Mean len ms/pass
baseline (no draft) 82.52 โ€” โ€” 12.12
master + DFlash 129.35 0.13673 (341/2494) 3.01 23.27
PR 26842 + DFlash 139.79 0.13673 (341/2494) 3.01 21.53

RTX 6000 PRO
151.39 tokens per second
llama-server -m muse-glimmer-30B-kquant-17gb.gguf -md dflash-kquant.gguf --spec-type draft-dflash --spec-draft-n-max 15 -ngl 99 -ngld 99 -fa on -c 8192 -np 1 --temp 0 --top-k 1 --jinja

Meta Inc. org
โ€ข
edited 1 day ago

Thanks for checking. So 233.4 tok/s is the mean, it's a wide interval as you can see from the image:
Screenshot 2026-08-10 at 3.44.53โ€ฏPM

Your request is definitely on the lower end, given the acceptance you are reporting. In general the dflash head has been mostly optimized for agentic and coding flows, so that's where I'd expect the highest speed-ups. Open-ended or subjective prompts I'd expect to be among the worst. But still we do see variance even within a specific category. If you were to sweep across a wider range of prompts I'd expect you to reach numbers closer to the mean we reported

Confirmed coding prompt performs really good with dflash
238.83t/s generation
draft acceptance = 0.28100 (784 accepted / 2790 generated), mean len = 5.22

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