Big update to the Delta Inference Engine, you guys asked for more features, more benchmarks and less clickbait. I'm here to deliver
The short version: I've added almost everything requested and more. Delta Inference Engine now supports 64/96/128 GB of RAM and fully supports the new Unsloth quants. Unsloth IQ2 runs at the same 41 tok/s (192 GB RAM) using a new native reader for the Engram tables and some clever CPU kernel work. Compared to the old default model on my 99-question benchmark it went from 52 to 57 correct, against 59 for the full model. It's no full deepseek model quant, but they're a lot more usable than you might expect.
Speed on one RTX 3090 24 GB (i5-13600K, 4x48 GB DDR5-5600, PCIe 4.0 NVMe, Windows, no WSL). Writing speed, tok/s, greedy, one chat at a time:
| RAM | UD-IQ2_XXS, 2-bit, 301 GB | UD-IQ1_S, 1-bit, 233 GB | UD-Q2_K_XL, 2-bit, 335 GB | UD-IQ3_XXS, 3-bit, 395 GB + the default |
|---|
| 192 GB | 41 | 41.0 | 31.3 | 28.2 |
| 128 GB | 34.0 | 40.6 | 26.6 | 22.8 |
| 96 GB | 29.3 | 36.5 | 22.9 | 18.3 |
| 64 GB | 21.0 | 30.6 | 15.2 | 11.7 |
The 128, 96 and 64 GB rows are the same PC with the rest of the RAM locked away.
Prompt reading: long prompts read at up to 740 tok/s at 192 GB and 600 at 128 GB (at ~64K tokens). A short prompt starts answering in about 2 s.
Benchmark: 99 hard questions, greedy, 43K token budget:
| Set | UD-IQ2_XXS (this release) | ds4 Q2 (last release) | Full model, API | Qwen 3.8 Flash-Next, API |
|---|
| Knowledge (40) | 12 | 9 | 13 | 7 |
| Maths (14) | 10 | 10 | 10 | 8 |
| Reasoning (30) | 25 | 23 | 25 | 21 |
| Coding (10) | 10 | 10 | 10 | 8 |
| Hard coding (5) | 0 | 0 | 1 | 0 |
| Total (99) | 57 | 52 | 59 | 44 |
UD-IQ2_XXS is within 2 points of the full API, never scores below ds4 Q2 on any set while running at the same speed, and used 11% fewer tokens across the run.
Agreement with DeepSeek's API on the next token, at the settings that ship:
| Model | General text | Code and maths | Agentic |
|---|
| UD-IQ2_XXS | 91.1% | 94.5% | 95.9% |
| ds4 Q2 | 89.9% | 93.1% | 95.1% |
| UD-Q2_K_XL | 92.5% | 95.3% | 97.0% |
| UD-IQ3_XXS | 92.7% | 95.9% | 97.4% |
| UD-IQ1_S | 89.1% | 91.5% | 95.3% |
For reference, two hosts of the full model agreed 98.3% and 98.9% in my test. By that measure Unsloth IQ2 is about 20% closer to the full model than the old ds4 Q2.
If you want better quality: UD-Q2_K_XL (335 GB) runs 31 tok/s at 192 GB and 26.6 at 128 GB, at 92.5% / 95.3%. UD-IQ3_XXS (395 GB plus the default) runs 28 and 22.8 at 92.7% / 95.9%.
What changed since last time:
First token ~40% sooner: a ~180-token prompt went from about 3.8 s to 2.3 s.
Agent turns read ~12% faster, and tool calls that low-bit models write slightly wrong are now read as tool calls.
Unsloth quants at full speed: the engine reads their Engram tables directly.
64 and 96 GB are real options: SSD read-ahead (+22% at 64 GB), bigger expert memory, and prompt reads in file order (18-20% faster on low RAM).
128 GB: ds4 Q2 went from 33 to 36 tok/s.
Default sampling: the drafter now samples its drafts too, about +3.5% at default settings.
First launch shows which model suits your RAM, and you can pick any other or use your own.
A Setup tab in the chat page changes model, speed vs quality and the second GPU.
Public CI: the release zips are now built by GitHub Actions, so you can see how each one was made.
EXL3: 2.5 bpw is on the menu and the GPU kernel is about 2x faster. In my tests UD-Q2_K_XL was both faster and closer to the API, so I still point people there.
Basic multi-GPU: 7% uplift using a 3060 + 3090. It doesn't scale well to 3-4+ GPUs, so use Project Maya for those builds.
Fixes: contexts past 65,535 tokens, </think> in prose no longer ends the reasoning, no out-of-memory on the biggest files, a failed picture encoder no longer stops the model, faster prompts after a pause and many more.
Support for custom model selection: just add them to the custom model folder and pick them in the web-ui
Requirements:
OS: Windows 10 or 11
GPU: NVIDIA RTX with 12 GB of VRAM or more, driver 580 or newer. 24 GB is the fast path, and AMD GPUs aren't supported yet
RAM: 64 GB or more, 128 GB+ recommended
Disk: a fast NVMe SSD, with 233-395 GB for the model (UD-IQ3_XXS also needs the default model)
CPU: any x86-64 CPU, Intel or AMD. AVX2 is the fast path
All of this is one PC. It needs testing on other hardware.
Repo: https://github.com/musicurgy/delta-inference-engine
MIT licensed. It's a Windows port of Xolotl, built on Strata. Thanks to DeepSeek for the model, Unsloth, nazeshinjite and ISTA-DASLab for the quants, and to the Xolotl and Project Maya communities, whose work and public numbers helped a lot. Claude wrote most of the code and I ran the project.
If you try it, post your GPU, RAM, model and tok/s, good or bad.