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ik_llama.cpp/github-data/pull_requests/130 - Q6_K_R4.md
2025-07-23 13:31:53 +02:00

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### 🔀 [#130](https://github.com/ikawrakow/ik_llama.cpp/pull/130) - Q6_K_R4
| **Author** | `ikawrakow` |
| :--- | :--- |
| **State** | ❌ **Closed** |
| **Created** | 2024-12-10 |
| **Updated** | 2024-12-10 |
---
#### Description
Follow up of #118, #119, #120, #121, #122, #123, #129 for `Q6_K`.
If nothing else `Q6_K` is routinely used for the output tensor, so having a better `Q6_K` performance would be useful.
We get a large speedup on `ARM_NEON` and non-negligible gains on `AVX2/Zen4`. Here is `PP-512` for LLaMA-3.1-8B on `Zen4` (Ryzen-7950X), `ARM_NEON` (M2-Max) and `AVX2` (Ryzen-5975WX)
| Platform | Threads | Q6_K | Q6_K_R4 | Speedup |
| ---: | ---: | ---: | ---: | ---: |
| ARM_NEON | 8 | 57.57 ± 0.61 | 83.25 ± 0.81 | 1.446 |
| Zen4 | 16 | 195.20 ± 0.74 | 243.25 ± 0.31 | 1.246 |
| AVX2 | 32 | 194.51 ± 0.35 | 264.16 ± 0.44 | 1.358 |
Except on `ARM_NEON`, where TG performance is slightly lower for small numbers of threads, we gain even for TG. Here results for TG-128 on LLaMA-3.1-8B with different numbers of threads:
| Platform | Threads | Q6_K | Q6_K_R4 | Speedup |
| ---: | ---: | ---: | ---: | ---: |
| ARM_NEON | 2 | 7.46 ± 0.03 | 7.35 ± 0.01 | 0.985 |
| | 4 | 13.88 ± 0.02 | 13.80 ± 0.01 | 0.994 |
| | 8 | 18.31 ± 0.16 | 18.57 ± 0.14 | 1.014 |
| Zen4 | 1 | 5.38 ± 0.00 | 7.94 ± 0.00 | 1.476 |
| | 2 | 8.93 ± 0.00 | 10.38 ± 0.00 | 1.162 |
| | 4 | 9.97 ± 0.27 | 10.18 ± 0.01 | 1.021 |
| AVX2 | 2 | 4.75 ± 0.00 | 5.78 ± 0.01 | 1.217 |
| | 4 | 7.57 ± 0.00 | 8.47 ± 0.00 | 1.119 |
| | 8 | 8.23 ± 0.00 | 9.14 ± 0.00 | 1.111 |
With this Zen4 implementation, for TG the available memory bandwidth is fully saturated with just 2 threads!