Fonzie0.2-4B-GGUF

GGUF files of Fonzie0.2-4B: a Qwen3.5-4B fine-tune that searches when it doesn't know, answers with sources, speaks Italian and English, and looks at pictures. It is trained to work inside agent apps (oh-my-pi, opencode). Compared to Fonzie0.1 it tries again after a failed search, searches first for "the latest X", says when something doesn't exist, and asks the user with the ask tool in oh-my-pi. Evaluation, limits and training details are in the model card of the full model, Fonzie0.2-4B.

File Size Use
Fonzie0.2-4B-Q8_0.gguf 4.6 GB closest to the bf16; not evaluated yet
Fonzie0.2-4B-Q4_K_M.gguf 2.8 GB smaller and faster; evaluated against the bf16 below
mmproj-Fonzie0.2-4B-F16.gguf 0.7 GB vision projector, needed for pictures

Made with llama.cpp (convert_hf_to_gguf.py, llama-quantize). The Q4_K_M is quantized from an F16 conversion. The evaluations in the model card of Fonzie0.2-4B used the bf16 model; the Q4_K_M was evaluated separately, below.

Memory by context

GPU memory used by llama-server with the vision projector loaded, MTP on and the default f16 KV cache:

Context (tokens) Q4_K_M Q8_0
8,192 4.2 GiB 5.9 GiB
32,768 5.1 GiB 6.8 GiB
65,536 6.3 GiB 8.0 GiB
131,072 8.7 GiB 10.4 GiB
163,840 10.1 GiB 11.8 GiB
262,144 (the model's limit) โ‰ฅ 13.4 GiB โ‰ฅ 15.1 GiB
  • Measured: the Q4_K_M on an RTX 4070 Ti (12 GB) at 64k, 128k and 160k, the last two with a prompt as long as the context.
  • Computed: the other Q4_K_M rows are the measured fixed part (3.9 GiB) plus about 38 KB per token. The Q8_0 rows add its bigger file (1.7 GiB) to the Q4_K_M; the Q8_0 itself was not run.
  • q8_0 KV cache (-ctk q8_0 -ctv q8_0): less than half the memory per token. On the 12 GB card the Q4_K_M then fits 229,376 tokens with the projector (10.0 GiB at peak), or the full 262,144 for text only (10.0 GiB).
  • Without MTP and without the projector the fixed part drops to 3.0 GiB.
  • Desktop apps hold memory on the same card: leave a margin.

How much the Q4_K_M loses

The same suites as the model card, Q4_K_M on llama-server against bf16 on vLLM 0.32. Bold marks the differences whose paired 95% interval excludes zero.

bf16 Q4_K_M
frozen test: accuracy 66.5% 64.8%
frozen test: confident wrong answers 24.6% 27.4%
frozen test: invented links 2.6% 7.2%
everyday questions, accuracy (oh-my-pi / opencode / Hermes) 66.9 / 66.7 / 76.4% 54.2 / 66.7 / 73.2%
new test set, accuracy (oh-my-pi / opencode / Hermes) 55.4 / 61.1 / 67.8% 52.1 / 67.2 / 60.6%

In opencode and Hermes the Q4_K_M is as good as the bf16, within the noise. In oh-my-pi it loses about 13 points on everyday questions, and it writes more links that no tool returned. These runs can't separate the 4-bit weights from the engine (llama.cpp instead of vLLM).

Speed on an RTX 4070 Ti, one user: 118.1 tokens/s, 157.0 with MTP 2 (the model's own multi-token prediction head, used for speculative decoding).

Usage

  • LM Studio: load the model file together with the mmproj file.

  • llama.cpp:

    llama-server -m Fonzie0.2-4B-Q4_K_M.gguf --mmproj mmproj-Fonzie0.2-4B-F16.gguf --jinja -c 65536 \
      --temp 1.0 --top-p 0.95 --top-k 20 --min-p 0
    
  • A 12 GB card, the fastest setup measured (llama.cpp 876a43211), with MTP 2 and a q8_0 KV cache:

    llama-server -m Fonzie0.2-4B-Q4_K_M.gguf --mmproj mmproj-Fonzie0.2-4B-F16.gguf -ngl 99 -np 1 \
      -c 229376 -ctk q8_0 -ctv q8_0 --spec-type draft-mtp --spec-draft-n-max 2 \
      --jinja --reasoning-format deepseek --temp 1.0 --top-p 0.95 --top-k 20 --min-p 0
    

Give it a web search tool: without tools and a system prompt it falls back to the base model's long thinking.

License: Apache 2.0, like the base model Qwen3.5-4B.

Author: Alfonso Fortunato.

Downloads last month
66
GGUF
Model size
4B params
Architecture
qwen35
Hardware compatibility
Log In to add your hardware

4-bit

8-bit

Inference Providers NEW
This model isn't deployed by any Inference Provider. ๐Ÿ™‹ Ask for provider support

Model tree for devopsfortunato/Fonzie0.2-4B-GGUF

Finetuned
Qwen/Qwen3.5-4B
Quantized
(603)
this model