alt.freeweights.text / Mellum2-12B-A2.5B-Instruct-GGUF
From: bartowski <huggingface.co/bartowski>Newsgroups: alt.freeweights.textSubject:

Mellum2-12B-A2.5B-Instruct-GGUF

Date: 2026-11-15Commit: 978d3b6Signed: 2DC28CC7B26A283B ✓

Text generation model. Gguf weights, 208 GB in all. Published by bartowski under Apache-2.0.

text208GBMellum2-12B-A2.5B-Instruct-GGUFggufpermissive
FactsParamsnot statedSize208 GBFormatsggufTasktext generationLicenseApache-2.0From sourcepermissive
$ fw get bartowski/Mellum2-12B-A2.5B-Instruct-GGUF
# manifest sha256 509fcab1feef… · 208 GB · 29 files
$ fw verify ./Mellum2-12B-A2.5B-Instruct-GGUF bartowski/Mellum2-12B-A2.5B-Instruct-GGUF
From sourceHosted (signed)bartowski/Mellum2-12B-A2.5B-Instruct-GGUFLast check: 2026-11-15 04:58 UTC

Get help: custom fine-tune or private deploy. We review your setup before we quote.

Quantized of Mellum2-12B-A2.5B-Instruct.

Works with

Convert with

Overview

Size
208 GB
Weights
41.0 MB (smallest of 27 GGUF variants)
Parameters
not stated
Formats
gguf
Task
text generation
License
Apache-2.0 (permissive)
Files
29, each with a sha256
Publisher
bartowski
Added
2026-11-15
Section
alt.freeweights.text
Lineage

Original release from the publisher.

Base model: JetBrains/Mellum2-12B-A2.5B-Instruct

Where these bytes come from
Publisher at the pinned commit→You

Sources are tried in order. A file counts only when its size and sha256 match the manifest. Sources are checked when you ask for them, not on a timer.

Sources
BadgeHostLast checkResult
From sourcehuggingface.co2026-11-15 04:58 UTCpassed

Model card

From the publisher at commit 978d3b6. Shown as plain text with links; images open at the publisher.

Llamacpp imatrix Quantizations of Mellum2-12B-A2.5B-Instruct by JetBrains#

Using llama.cpp release b9590 for quantization.

Original model: https://huggingface.co/JetBrains/Mellum2-12B-A2.5B-Instruct

All quants made using imatrix option with dataset from here

Run them in your choice of tools:

Note: if it's a newly supported model, you may need to wait for an update from the developers.

Prompt format#

<|im_start|>system
{system_prompt}<|im_end|>
<|im_start|>user
{prompt}<|im_end|>
<|im_start|>assistant

Download a file (not the whole branch) from below:#

FilenameQuant typeFile SizeSplitDescription
Mellum2-12B-A2.5B-Instruct-bf16.ggufbf1624.31GBfalseFull BF16 weights.
Mellum2-12B-A2.5B-Instruct-Q8_0.ggufQ8_012.93GBfalseExtremely high quality, generally unneeded but max available quant.
Mellum2-12B-A2.5B-Instruct-Q6_K_L.ggufQ6_K_L11.10GBfalseUses Q8_0 for embed and output weights. Very high quality, near perfect, recommended.
Mellum2-12B-A2.5B-Instruct-Q6_K.ggufQ6_K10.99GBfalseVery high quality, near perfect, recommended.
Mellum2-12B-A2.5B-Instruct-Q5_K_L.ggufQ5_K_L9.43GBfalseUses Q8_0 for embed and output weights. High quality, recommended.
Mellum2-12B-A2.5B-Instruct-Q5_K_M.ggufQ5_K_M9.29GBfalseHigh quality, recommended.
Mellum2-12B-A2.5B-Instruct-Q5_K_S.ggufQ5_K_S8.67GBfalseHigh quality, recommended.
Mellum2-12B-A2.5B-Instruct-Q4_K_L.ggufQ4_K_L8.34GBfalseUses Q8_0 for embed and output weights. Good quality, recommended.
Mellum2-12B-A2.5B-Instruct-Q4_K_M.ggufQ4_K_M8.17GBfalseGood quality, default size for most use cases, recommended.
Mellum2-12B-A2.5B-Instruct-Q4_1.ggufQ4_17.71GBfalseLegacy format, similar performance to Q4_K_S but with improved tokens/watt on Apple silicon.
Mellum2-12B-A2.5B-Instruct-Q4_K_S.ggufQ4_K_S7.56GBfalseSlightly lower quality with more space savings, recommended.
Mellum2-12B-A2.5B-Instruct-IQ4_NL.ggufIQ4_NL7.01GBfalseSimilar to IQ4_XS, but slightly larger. Offers online repacking for ARM CPU inference.
Mellum2-12B-A2.5B-Instruct-Q4_0.ggufQ4_07.00GBfalseLegacy format, offers online repacking for ARM and AVX CPU inference.
Mellum2-12B-A2.5B-Instruct-IQ4_XS.ggufIQ4_XS6.77GBfalseDecent quality, smaller than Q4_K_S with similar performance, recommended.
Mellum2-12B-A2.5B-Instruct-Q3_K_XL.ggufQ3_K_XL6.46GBfalseUses Q8_0 for embed and output weights. Lower quality but usable, good for low RAM availability.
Mellum2-12B-A2.5B-Instruct-IQ3_M.ggufIQ3_M6.33GBfalseMedium-low quality, new method with decent performance comparable to Q3_K_M.
Mellum2-12B-A2.5B-Instruct-Q3_K_L.ggufQ3_K_L6.26GBfalseLower quality but usable, good for low RAM availability.
Mellum2-12B-A2.5B-Instruct-Q3_K_M.ggufQ3_K_M6.18GBfalseLow quality.
Mellum2-12B-A2.5B-Instruct-IQ3_XS.ggufIQ3_XS6.18GBfalseLower quality, new method with decent performance, slightly better than Q3_K_S.
Mellum2-12B-A2.5B-Instruct-Q3_K_S.ggufQ3_K_S5.95GBfalseLow quality, not recommended.
Mellum2-12B-A2.5B-Instruct-IQ3_XXS.ggufIQ3_XXS5.80GBfalseLower quality, new method with decent performance, comparable to Q3 quants.
Mellum2-12B-A2.5B-Instruct-Q2_K_L.ggufQ2_K_L5.38GBfalseUses Q8_0 for embed and output weights. Very low quality but surprisingly usable.
Mellum2-12B-A2.5B-Instruct-Q2_K.ggufQ2_K5.16GBfalseVery low quality but surprisingly usable.
Mellum2-12B-A2.5B-Instruct-IQ2_M.ggufIQ2_M5.10GBfalseRelatively low quality, uses SOTA techniques to be surprisingly usable.
Mellum2-12B-A2.5B-Instruct-IQ2_S.ggufIQ2_S4.87GBfalseLow quality, uses SOTA techniques to be usable.
Mellum2-12B-A2.5B-Instruct-IQ2_XS.ggufIQ2_XS4.81GBfalseLow quality, uses SOTA techniques to be usable.

Embed/output weights#

Some of these quants (Q3_K_XL, Q4_K_L etc) are the standard quantization method with the embeddings and output weights quantized to Q8_0 instead of what they would normally default to.

Downloading using huggingface-cli#

Click to view download instructions

First, make sure you have hugginface-cli installed:

pip install -U "huggingface_hub[cli]"

Then, you can target the specific file you want:

huggingface-cli download bartowski/Mellum2-12B-A2.5B-Instruct-GGUF --include "Mellum2-12B-A2.5B-Instruct-Q4_K_M.gguf" --local-dir ./

If the model is bigger than 50GB, it will have been split into multiple files. In order to download them all to a local folder, run:

huggingface-cli download bartowski/Mellum2-12B-A2.5B-Instruct-GGUF --include "Mellum2-12B-A2.5B-Instruct-Q8_0/*" --local-dir ./

You can either specify a new local-dir (Mellum2-12B-A2.5B-Instruct-Q8_0) or download them all in place (./)

ARM/AVX information#

Previously, you would download Q4_0_4_4/4_8/8_8, and these would have their weights interleaved in memory in order to improve performance on ARM and AVX machines by loading up more data in one pass.

Now, however, there is something called "online repacking" for weights. details in this PR. If you use Q4_0 and your hardware would benefit from repacking weights, it will do it automatically on the fly.

As of llama.cpp build b4282 you will not be able to run the Q4_0_X_X files and will instead need to use Q4_0.

Additionally, if you want to get slightly better quality for , you can use IQ4_NL thanks to this PR which will also repack the weights for ARM, though only the 4_4 for now. The loading time may be slower but it will result in an overall speed incrase.

Click to view Q4_0_X_X information (deprecated

I'm keeping this section to show the potential theoretical uplift in performance from using the Q4_0 with online repacking.

Click to view benchmarks on an AVX2 system (EPYC7702)

modelsizeparamsbackendthreadstestt/s% (vs Q4_0)
qwen2 3B Q4_01.70 GiB3.09 BCPU64pp512204.03 ± 1.03100%
qwen2 3B Q4_01.70 GiB3.09 BCPU64pp1024282.92 ± 0.19100%
qwen2 3B Q4_01.70 GiB3.09 BCPU64pp2048259.49 ± 0.44100%
qwen2 3B Q4_01.70 GiB3.09 BCPU64tg12839.12 ± 0.27100%
qwen2 3B Q4_01.70 GiB3.09 BCPU64tg25639.31 ± 0.69100%
qwen2 3B Q4_01.70 GiB3.09 BCPU64tg51240.52 ± 0.03100%
qwen2 3B Q4_K_M1.79 GiB3.09 BCPU64pp512301.02 ± 1.74147%
qwen2 3B Q4_K_M1.79 GiB3.09 BCPU64pp1024287.23 ± 0.20101%
qwen2 3B Q4_K_M1.79 GiB3.09 BCPU64pp2048262.77 ± 1.81101%
qwen2 3B Q4_K_M1.79 GiB3.09 BCPU64tg12818.80 ± 0.9948%
qwen2 3B Q4_K_M1.79 GiB3.09 BCPU64tg25624.46 ± 3.0483%
qwen2 3B Q4_K_M1.79 GiB3.09 BCPU64tg51236.32 ± 3.5990%
qwen2 3B Q4_0_8_81.69 GiB3.09 BCPU64pp512271.71 ± 3.53133%
qwen2 3B Q4_0_8_81.69 GiB3.09 BCPU64pp1024279.86 ± 45.63100%
qwen2 3B Q4_0_8_81.69 GiB3.09 BCPU64pp2048320.77 ± 5.00124%
qwen2 3B Q4_0_8_81.69 GiB3.09 BCPU64tg12843.51 ± 0.05111%
qwen2 3B Q4_0_8_81.69 GiB3.09 BCPU64tg25643.35 ± 0.09110%
qwen2 3B Q4_0_8_81.69 GiB3.09 BCPU64tg51242.60 ± 0.31105%

Q4_0_8_8 offers a nice bump to prompt processing and a small bump to text generation

Which file should I choose?#

Click here for details

A great write up with charts showing various performances is provided by Artefact2 here

The first thing to figure out is how big a model you can run. To do this, you'll need to figure out how much RAM and/or VRAM you have.

If you want your model running as FAST as possible, you'll want to fit the whole thing on your GPU's VRAM. Aim for a quant with a file size 1-2GB smaller than your GPU's total VRAM.

If you want the absolute maximum quality, add both your system RAM and your GPU's VRAM together, then similarly grab a quant with a file size 1-2GB Smaller than that total.

Next, you'll need to decide if you want to use an 'I-quant' or a 'K-quant'.

If you don't want to think too much, grab one of the K-quants. These are in format 'QX_K_X', like Q5_K_M.

If you want to get more into the weeds, you can check out this extremely useful feature chart:

llama.cpp feature matrix

But basically, if you're aiming for below Q4, and you're running cuBLAS (Nvidia) or rocBLAS (AMD), you should look towards the I-quants. These are in format IQX_X, like IQ3_M. These are newer and offer better performance for their size.

These I-quants can also be used on CPU, but will be slower than their K-quant equivalent, so speed vs performance is a tradeoff you'll have to decide.

Credits#

Thank you kalomaze and Dampf for assistance in creating the imatrix calibration dataset.

Thank you ZeroWw for the inspiration to experiment with embed/output.

Thank you to LM Studio for sponsoring my work.

Want to support my work? Visit my ko-fi page here: https://ko-fi.com/bartowski

Files

29 files · 208 GBWeights 41.0 MB (smallest of 27 GGUF variants). Sizes and sha256 from the signed manifest.
Show all 29 files with their sha256
FileSizesha256
.gitattributes3.53 KB07ac2a66548727b235f4604c8848cb85aec9fceb920ce82b1de7501753abe279
Mellum2-12B-A2.5B-Instruct-IQ2_M.gguf5.10 GB75cefdc8839f505f83d394e2f996572e04502a35a9d176b0aae10d1953b29c13
Mellum2-12B-A2.5B-Instruct-IQ2_S.gguf4.87 GB249257f962802f231c318963f41a210206d9f88a296d415ba53509840165b58c
Mellum2-12B-A2.5B-Instruct-IQ2_XS.gguf4.81 GB654246a3a1e270fd761655341c6e44b3f0a923b688c773b8f28765b35dbbedad
Mellum2-12B-A2.5B-Instruct-IQ3_M.gguf6.33 GBaa2ef0959ed5aefa04148b8c2a3c77e0041660d4fe134a975c4565678363d199
Mellum2-12B-A2.5B-Instruct-IQ3_XS.gguf6.18 GB4e270afc99d246a22f2d1e2ffdfe2badfe58bfd18aa848d6b688a84e0c850841
Mellum2-12B-A2.5B-Instruct-IQ3_XXS.gguf5.80 GBa646ed7a019137dc3625519a6944a80ec781a80d9fd5c023bc39c19fd2d17c26
Mellum2-12B-A2.5B-Instruct-IQ4_NL.gguf7.01 GB625223cc4d0625094c89831dc6436fc493fde10677558b1428e6ef472f11b3e2
Mellum2-12B-A2.5B-Instruct-IQ4_XS.gguf6.77 GB9b34e7eddd1b4e30bcdcaf329f7f9e12d6f9bcce563dcb705147933e7c95b2d7
Mellum2-12B-A2.5B-Instruct-Q2_K.gguf5.16 GB1d476ac7020523ad0685544c11e2211b5688d872b7d26b43ed602c4e805e8fb4
Mellum2-12B-A2.5B-Instruct-Q2_K_L.gguf5.38 GBeed18fb6eaf51c7790deaf1dd475f7d4f3cf95f3b3feee36ec93d64589d0b4a4
Mellum2-12B-A2.5B-Instruct-Q3_K_L.gguf6.26 GB91cadd916d9235566882b0196f55dc096d142a2bd9d8162c9e0dd1624922a0fc
Mellum2-12B-A2.5B-Instruct-Q3_K_M.gguf6.18 GB7f3027a79225a2f3c7d4fe6bafc83f493361c290512c1901e984f451376ba6c7
Mellum2-12B-A2.5B-Instruct-Q3_K_S.gguf5.95 GBbb68601c7fcb5a3f5c73c823812dc72864bc51fb8d17ef2d756de5bb0a0e53d1
Mellum2-12B-A2.5B-Instruct-Q3_K_XL.gguf6.46 GBec902df24db444da374d64243147b134d33f14a6f9524dbcc234d20458849ea4
Mellum2-12B-A2.5B-Instruct-Q4_0.gguf7.00 GB25ba66f80c662041544f56c28fa6d340367de94db568a2c8c2611119cd9dac10
Mellum2-12B-A2.5B-Instruct-Q4_1.gguf7.71 GBc813e737fd6dd65beb674eeaf30e56a403098af5c840963bd13a6ee07f0c609f
Mellum2-12B-A2.5B-Instruct-Q4_K_L.gguf8.34 GB9c7af2867e20e512da205ba4a06c1217972ca7459b84f3b97c691f0ec67db565
Mellum2-12B-A2.5B-Instruct-Q4_K_M.gguf8.17 GB908b5d3968f400ed300a49b2b8b4e91ec805c3871a5594edcd2e3ed0eeea66de
Mellum2-12B-A2.5B-Instruct-Q4_K_S.gguf7.56 GBc6c07f62dcfb45f48e0f8e71bda340087087428b7bb99367736fc27fce9ef67b
Mellum2-12B-A2.5B-Instruct-Q5_K_L.gguf9.43 GB8e72130bddfe5d81ac3f1f8d03e3127e0691def923639aca3f41306265961b72
Mellum2-12B-A2.5B-Instruct-Q5_K_M.gguf9.29 GB33385f76cee115b971ff3d90ccb6c92c307acce05827f8822d9f1d4fd0b4a66f
Mellum2-12B-A2.5B-Instruct-Q5_K_S.gguf8.67 GB70bfd3821fc315f2541d89dea0ec5a294a1d3947f135c822a4f344a43983fcbd
Mellum2-12B-A2.5B-Instruct-Q6_K.gguf11.0 GBd4add4eba30ac7f366f64ea83bf5d5ac81d923b8fe768baa5963f0bee34aa4d7
Mellum2-12B-A2.5B-Instruct-Q6_K_L.gguf11.1 GBe973b8c16d5c226b8077ab034bf5107c9ade66b4b765b2023751cdacbd051ce8
Mellum2-12B-A2.5B-Instruct-Q8_0.gguf12.9 GB9cd25bf0a3f47366c968adadc07e3fa22b46a5c25b1b42bb2f0fd1861f6d9b53
Mellum2-12B-A2.5B-Instruct-bf16.gguf24.3 GB77bee217b7b822b2be6ee98a9aa7c813fa335302ce2d3c533565a0a897f1d64b
Mellum2-12B-A2.5B-Instruct-imatrix.gguf41.0 MBc60099e55d3a675ec52f6400b05a33e4b3ed2840edc12a7c0a91d2a721868d38
README.md18.0 KBfe375b68ab9b668a7108dbc18ced04006bd4611ffc41258c169cc808c7c8a671
VersionsEach time the pinned upstream commit or file list changed in this repo. Newest first.
Upstream commitDateContents
978d3b6338 pinned now2026-11-15 04:58 UTC29 files · 208 GB

Use it

$ fw get bartowski/Mellum2-12B-A2.5B-Instruct-GGUF
# manifest sha256 509fcab1feef… · 208 GB · 29 files
$ fw verify ./Mellum2-12B-A2.5B-Instruct-GGUF bartowski/Mellum2-12B-A2.5B-Instruct-GGUF
fw.pyChecks the signature and every sha256, tries each source in order, resumes.
$ python3 fw.py get https://freeweights.allternit.com/manifests/bartowski/Mellum2-12B-A2.5B-Instruct-GGUF.json --dir ./Mellum2-12B-A2.5B-Instruct-GGUF $ python3 fw.py verify ./Mellum2-12B-A2.5B-Instruct-GGUF ./bartowski__Mellum2-12B-A2.5B-Instruct-GGUF.json
hfThe Hugging Face CLI with one setting. Same repo id.
$ HF_ENDPOINT=https://freeweights.allternit.com hf download bartowski/Mellum2-12B-A2.5B-Instruct-GGUF --revision 978d3b633817824470ef48a53141e3dccf1863f0 --local-dir ./Mellum2-12B-A2.5B-Instruct-GGUF
llama.cppDownload one GGUF variant (Mellum2-12B-A2.5B-Instruct-imatrix, 41.0 MB), then serve it.
$ HF_ENDPOINT=https://freeweights.allternit.com hf download bartowski/Mellum2-12B-A2.5B-Instruct-GGUF --include "Mellum2-12B-A2.5B-Instruct-imatrix*" --local-dir ./Mellum2-12B-A2.5B-Instruct-GGUF $ llama-server -m ./Mellum2-12B-A2.5B-Instruct-GGUF/Mellum2-12B-A2.5B-Instruct-imatrix.gguf
OllamaMake an Ollama model from the downloaded file.
$ printf 'FROM ./Mellum2-12B-A2.5B-Instruct-GGUF/Mellum2-12B-A2.5B-Instruct-imatrix.gguf\n' > Modelfile $ ollama create mellum2-12b-a2.5b-instruct-gguf -f Modelfile

License

Name
Apache License 2.0
Id
Apache-2.0
Class
Permissive
Redistribution
yes
Listing
Hosted (signed)
Decided
License as declared by the publisher. No person read it. 2026-11-15
Text in
README.md
Text sha256
fe375b68ab9b668a7108dbc18ced04006bd4611ffc41258c169cc808c7c8a671
Terms gate
No extra terms beyond the license.

Read the license text

Licenses are checked against the license table. A custom license passes only after a person reads it.

Provenance

From: bartowski <huggingface.co/bartowski>Newsgroups: alt.freeweights.textSubject: Mellum2-12B-A2.5B-Instruct-GGUFDate: 2026-11-15Commit: 978d3b6Signed: 2DC28CC7B26A283B ✓
Upstream
bartowski/Mellum2-12B-A2.5B-Instruct-GGUF
Pinned commit
978d3b633817824470ef48a53141e3dccf1863f0
Manifest
Mellum2-12B-A2.5B-Instruct-GGUF.json · .minisig
Manifest sha256
509fcab1feef2c8f5a433fb19773f7dad8201b5fc3d4b602f112734e037bda38
Signature
minisign, Ed25519, key 2DC28CC7B26A283B
Created
2026-11-15 04:58 UTC
Generator
freeweights-manifest/0.1.0
Takedowns
None.

How to verify

$ curl -O https://freeweights.allternit.com/manifests/bartowski/Mellum2-12B-A2.5B-Instruct-GGUF.json $ curl -O https://freeweights.allternit.com/manifests/bartowski/Mellum2-12B-A2.5B-Instruct-GGUF.json.minisig $ minisign -Vm Mellum2-12B-A2.5B-Instruct-GGUF.json -P RWQ7KGqyx4zCLXtUFOqvfv8L3g+8fpKJ1FsuxPyOYMF+4KufbUxKq1Oq $ shasum -a 256 <file> # compare with the Files tab

A manifest whose signature fails must be rejected. A file whose size or sha256 does not match must be discarded. Verify a download

Model tree

Parent

JetBrains/Mellum2-12B-A2.5B-Instruct · this model is a quantization of it

No model in the catalog names this one as its parent.

Get it
Download
$ HF_ENDPOINT=https://freeweights.allternit.com hf download bartowski/Mellum2-12B-A2.5B-Instruct-GGUF
Open in Freeweights Studio

Pull, verify and run it in the Allternit app on Desktop, web or phone.

Signed manifest
minisign, key 2DC28CC7B26A283B. Mellum2-12B-A2.5B-Instruct-GGUF.json. Provenance. Takedown history: none.
From: laion <huggingface.co/laion>Subject: a2-rl-e2egit_large-50-32B
From: laion <huggingface.co/laion>Subject: a3-rl-DCAgent_exp_rpt_e2egit-large-15-8B
From: laion <huggingface.co/laion>Subject: a3-rl-DCAgent_exp_rpt_e2egit-v2-10-8B
From: laion <huggingface.co/laion>Subject: a3-rl-DCAgent_exp_rpt_pymethods2test-large-80-8B
From: laion <huggingface.co/laion>Subject: a3-rl-DCAgent_exp_rpt_unitsyn-python-large-10-8B
From: laion <huggingface.co/laion>Subject: a3-rl-DCAgent_mix_h2_language_proportional-65-8B