Synth 2.5 Pro Preview
[!Note] This is a preview model, it may deliver performance below that of the final model. This preview is a model finetuned with purely SFT, RLAIF has not been applied yet. Alongside this, creative performance is currently best on non-thinking mode for this preview.
Synth 2.5 Pro is the next model in the Synth line-up, based on Gemma 4 26BA4B, it has 26B total parameters and 4B active parameters.
Compared to Synth 2
Compared to Synth 2, 2.5 has the following changes/improvements:
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Trained on real-world creative data/usage from SOTA models (and past-sota, user-perferred models)
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Optimized for following user-wanted qualities (described here) via RLAIF (READ NOTE FOR PREVIEW)
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Hybrid reasoning support, for optional further in-depth creative reasoning
Usage
Composite and LuciditySH Platform
You can test Synth 2.5 Pro at Composite (creative specific) or LuciditySH Platform (coming soon) for free, with up to 100 free requests a day for easy testing/usage.
Local
You can use Synth 2.5 Pro on Llama.cpp or VLLM
Generation Parameters
It is recommended to use Synth 2.5 Pro with the following generation settings:
- Temperature: 0.8-1
- Top-P: 0.95
- Top-K: 0
Training
For the SFT stage of Synth 2.5's training, it was trained on a closed dataset comprised of real-world creative interactions with the following models, with the amount of interactions:
| Family | Samples |
|---|---|
| Gemini (2.5 Pro) | 1 |
| Gemini (3.X Pro/3.7) | 1 |
| DeepSeek (V3 0324) | 5 |
| DeepSeek (R1 0528) | 8 |
| DeepSeek (V4 Pro) | 804 |
| GLM (5.X) | 1981 |
| GLM (4.X) | 58 |
| Kimi (k2.X) | 284 |
| Kimi (k3) | 3 |
| Minimax M3 | 69 |
| StepFun | 40 |
| total | 3254 |
For model replication, close data to our closed dataset can be found in our PIPKIN datasets.
Limitations (for Preview)
As per the active parameter count of this model (4B) and the fact that it is only in preview, it comes with the following limitations, as flagged by Composite users:
- Synth 2.5 Pro Preview is unstable at higher temperatures (<1)
- Synth 2.5 Pro Preview may seem predictable, even at a higher temperature (0.8-1)
Considerations
Synth 2.5 Pro is capable of generating content that is harmful, illegal and/or generally NSFW, as with any LLM. It is recommended to put Synth 2.5 behind a moderation model or other safety layer for real world deployment.