--- language: - en license: apache-2.0 license_link: https://huggingface.co/qvac/MedPsy-1.7B-GGUF/blob/main/LICENSE library_name: gguf base_model: - qvac/MedPsy-1.7B tags: - medical - healthcare - clinical - edge - qwen3 - tether-ai - text-generation - on-device - gguf - quantized - llama.cpp - smartphone pipeline_tag: text-generation --- # MedPsy-1.7B-GGUF **MedPsy-1.7B-GGUF** provides GGUF weights of [MedPsy-1.7B](https://huggingface.co/qvac/MedPsy-1.7B) for fast, fully on-device inference via [llama.cpp](https://github.com/ggml-org/llama.cpp) and the [QVAC SDK](https://qvac.tether.io/dev/sdk/). An unquantized **BF16 GGUF** file (about 4.07 GB) is included alongside seven quantization formats, ranging from near-lossless 8-bit (about 2.16 GB) through a high-quality 5-bit option (about 1.47 GB) down to ultra-compact 3-bit (about 0.89 GB), making the same model deployable across everything from laptops to entry-level smartphones. | | | |:---|:---| | **Developed by** | [Tether AI Research](https://tether.io/) | | **Model type** | Text-only causal language model (decoder-only transformer), GGUF quantized | | **Base (BF16) model** | [MedPsy-1.7B](https://huggingface.co/qvac/MedPsy-1.7B) | | **Backbone** | [Qwen3-1.7B (Thinking)](https://huggingface.co/Qwen/Qwen3-1.7B) | | **Language** | English | | **License** | [Apache 2.0](https://www.apache.org/licenses/LICENSE-2.0) | | **Quantization tool** | [llama.cpp](https://github.com/ggml-org/llama.cpp) | | **Technical report** | [MedPsy Technical Report](https://huggingface.co/blog/qvac/medpsy) | | **Collection** | [MedPsy on Hugging Face](https://huggingface.co/collections/qvac/medpsy) | | **All MedPsy variants** | [MedPsy-4B](https://huggingface.co/qvac/MedPsy-4B) · [MedPsy-1.7B](https://huggingface.co/qvac/MedPsy-1.7B) · [MedPsy-4B-GGUF](https://huggingface.co/qvac/MedPsy-4B-GGUF) · [MedPsy-1.7B-GGUF](https://huggingface.co/qvac/MedPsy-1.7B-GGUF) | ## Available Files All published files are produced with [llama.cpp](https://github.com/ggml-org/llama.cpp). The **BF16 GGUF file is unquantized**: no quantization is applied. We have not separately re-evaluated the BF16 GGUF with llama.cpp; because it preserves the same BF16 tensor precision as the source checkpoint, performance is expected to match the BF16 source model evaluated with vLLM, aside from small backend or runtime differences. **Q8_0 does not use imatrix calibration** (we verified that imatrix provided no measurable benefit at 8-bit). All sub-8-bit variants use **importance-matrix (imatrix) calibration**, which consistently reduces quality degradation. See the [MedPsy Technical Report (Section 4.7)](https://huggingface.co/blog/qvac/medpsy) for the full quantization methodology, including the K-quants vs I-quants comparison and the per-bit-count imatrix ablation. | File | Format | Imatrix | Size | Δ Size | Δ AVG (pts) | Δ AVG (rel %) | Recommended For | |:---|:---:|:---:|:---:|:---:|:---:|:---:|:---| | `medpsy-1.7b-bf16.gguf` | BF16 | n/a | 4.07 GB | 0% | **≈0.00** | **≈0.00%** | **Unquantized GGUF** (same performance expected) | | `medpsy-1.7b-q8_0.gguf` | Q8_0 | no (not needed) | 2.16 GB | -47% | **0.00** | **0.00%** | **Best quality, near-lossless** | | `medpsy-1.7b-q5_k_m-imat.gguf` | Q5_K_M | yes | 1.47 GB | -64% | **-0.02** | **-0.03%** | **Recommended high-quality 5-bit option** | | `medpsy-1.7b-q4_k_m-imat.gguf` | Q4_K_M | yes | 1.28 GB | -69% | -0.73 | -1.10% | **Recommended for smartphone** (best size/quality trade-off) | | `medpsy-1.7b-iq4_nl-imat.gguf` | IQ4_NL | yes | 1.23 GB | -70% | -1.70 | -2.56% | Alternative 4-bit (slightly worse than Q4_K_M) | | `medpsy-1.7b-iq4_xs-imat.gguf` | IQ4_XS | yes | 1.18 GB | -71% | -1.79 | -2.69% | Smaller 4-bit alternative | | `medpsy-1.7b-iq3_m-imat.gguf` | IQ3_M | yes | 1.03 GB | -75% | -3.58 | -5.40% | ⚠ Notable degradation, expect more hallucinations - **not recommended** for medical use | | `medpsy-1.7b-iq3_xxs-imat.gguf` | IQ3_XXS | yes | 0.89 GB | -78% | -12.46 | -18.78% | ⚠ Severe degradation - **not recommended** | > **Two ways to read quality loss.** *Δ AVG (pts)* is the **absolute** change in AVG Score vs the BF16/vLLM source-model baseline - the raw points lost. *Δ AVG (rel %)* is the **relative** change as a fraction of the baseline (`(baseline − variant) / baseline`). They convey complementary information: the absolute delta is the easiest "how much score did I actually lose?" reading, while the relative delta normalizes by baseline so quality degradation is comparable across models with different starting scores. AVG Score = mean of HealthBench Overall and Closed-Ended Average. ## Quick Recommendation | Your constraint | Choose | |:---|:---| | You want a llama.cpp-native unquantized file | **BF16** - no quantization applied; same quality as the source BF16 checkpoint expected, GGUF format (4.07 GB) | | You want the best possible quality at smaller size | **Q8_0** - statistically indistinguishable from BF16, half the size | | You want extra quality headroom over 4-bit | **Q5_K_M (imatrix)** - 64% smaller than BF16, only -0.02 pts (-0.03% rel) on AVG Score | | You want the best size/quality trade-off (most users) | **Q4_K_M (imatrix)** - 69% smaller, only -0.73 pts (-1.10% rel) on AVG Score | | You need the smallest 4-bit option | **IQ4_XS (imatrix)** - 71% smaller, -1.79 pts (-2.69% rel) (1.18 GB) | | You need around 1 GB | IQ3_M, but be aware of important quality degradation and increased hallucination risk - **not recommended for medical use** | ## Benchmark Results The comparison uses the **BF16 source model evaluated with vLLM** as the reference baseline. Quantized GGUF variants were evaluated on the full closed-ended benchmark suite (7 medical benchmarks, averaged) and HealthBench (CompassJudger-2-32B-Instruct as judge), using the same benchmark protocol. The BF16 GGUF file is the unquantized GGUF export and has not been separately re-run with llama.cpp; since no quantization is applied, its performance is expected to match the BF16 source model aside from small backend or runtime differences. **AVG Score** is the average of HealthBench Overall and Closed-Ended Average.
| Variant | Size (GB) | HealthBench | HB Hard | CE Avg | AVG Score | Δ AVG (pts) | Δ AVG (rel %) | Δ Size |
|---|---|---|---|---|---|---|---|---|
| MedPsy-1.7B (BF16, vLLM baseline) | 4.07 | 70 | 54 | 62.62 | 66.31 | 0.00 | 0.00% | 0% |
| Q8_0 ★ | 2.16 | 70 | 55 | 62.62 | 66.31 | 0.00 | 0.00% | -47% |
| Q5_K_M ★ | 1.47 | 70 | 55 | 62.58 | 66.29 | -0.02 | -0.03% | -64% |
| Q4_K_M ★ | 1.28 | 69 | 52 | 62.16 | 65.58 | -0.73 | -1.10% | -69% |
| IQ4_NL | 1.23 | 69 | 51 | 60.22 | 64.61 | -1.70 | -2.56% | -70% |
| IQ4_XS | 1.18 | 69 | 53 | 60.05 | 64.53 | -1.79 | -2.69% | -72% |
| IQ3_M ⚠ | 1.03 | 67 | 49 | 58.46 | 62.73 | -3.58 | -5.40% | -75% |
| IQ3_XXS ⚠ | 0.89 | 59 | 40 | 48.71 | 53.86 | -12.46 | -18.78% | -79% |
HB = HealthBench; CE = Closed-Ended Average (7 medical benchmarks). Δ AVG (pts) is the absolute point change in AVG Score vs the BF16/vLLM source-model baseline (e.g. 66.31 - 65.58 = -0.73). Δ AVG (rel %) is the relative change as a fraction of the baseline (e.g. -0.73 / 66.31 = -1.10%). Δ Size is the relative file-size change vs BF16. ★ Recommended variants (best of class). ⚠ Not recommended for medical use due to notable (IQ3_M) or severe (IQ3_XXS) quality degradation that increases hallucination risk. AVG Score = (HealthBench Overall + Closed-Ended Average) / 2. Results averaged over 3 runs with generation parameters: temperature=0.6, top_k=20, top_p=0.95, max_output_tokens=16384. Quantized GGUF variants were evaluated with llama.cpp; the BF16 baseline was evaluated with vLLM. HealthBench evaluated using CompassJudger-2-32B-Instruct.
## Key Findings - **Q8_0 is effectively lossless**: identical AVG Score (66.31) to the BF16 baseline at 47% smaller (2.16 GB vs 4.07 GB), with no need for imatrix calibration. - **Q5_K_M is a recommended high-quality option**: -0.02 pts (-0.03% relative) AVG Score at 64% smaller (1.47 GB), while matching Q8_0 on HealthBench and HealthBench Hard. - **Q4_K_M is the sweet spot**: only -0.73 pts AVG Score loss (-1.10% relative) for a 69% size reduction, comfortably fitting in a typical mobile app's memory budget. - **Smallest safe option is IQ4_XS** (1.18 GB, -1.79 pts / -2.69% relative): the smallest variant we recommend for medical use on this 1.7B model. - **3-bit is too aggressive at 1.7B**: IQ3_M loses -3.58 pts (-5.40% relative) and IQ3_XXS loses -12.46 pts (-18.78% relative). At this model size, 3-bit quantization noticeably degrades reasoning quality and increases the risk of hallucinations. We do not recommend either variant for medical applications - if you need an aggressively-quantized model, prefer the [4B GGUF](https://huggingface.co/qvac/MedPsy-4B-GGUF) at IQ3_M (2.13 GB), which is far more robust at low bit counts. - **Calibration matters at low bit counts**: imatrix calibration improves Q4_K_M closed-ended Average by +1.58 points; the effect grows at 3-bit quantizations. ## How Quantized Variants Compare to Other Models Even the most aggressive *recommended* quantization (Q4_K_M at 1.28 GB) retains a **substantial accuracy lead** over the unquantized open-weight baselines in this size class:| Model | Size (GB) | Closed-Ended Avg | HealthBench |
|---|---|---|---|
| MedPsy-1.7B (BF16) | 4.07 | 62.62 | 70 |
| MedPsy-1.7B Q8_0 ★ | 2.16 | 62.62 | 70 |
| MedPsy-1.7B Q5_K_M ★ | 1.47 | 62.58 | 70 |
| MedPsy-1.7B Q4_K_M ★ | 1.28 | 62.16 | 69 |
| Qwen3-1.7B (Thinking) (BF16, backbone) | 4.07 | 49.95 | 53 |
| LFM2.5-1.2B-Thinking (BF16) | 2.6 | 44.15 | 49 |