Q4 Quant Benchmarks Crown Top Quants

๐กData-driven Q4 quant picks for Qwen3.5-35B: save VRAM, keep quality
โก 30-Second TL;DR
What Changed
KLD measures quantization drift from BF16 baseline; lower is better
Why It Matters
Guides practitioners to optimal quants, saving VRAM while preserving model quality for local inference.
What To Do Next
Download AesSedai_Qwen3.5-35B-A3B-IQ4_XS for top efficiency quant.
Key Points
- โขKLD measures quantization drift from BF16 baseline; lower is better
- โขAesSedai Q4_K_M best at KLD 0.0102 via Q8_0 on attention/experts
- โขUbergarm Q4_0 outperforms others by 2.5x margin
- โขMXFP4 underperforms post-hoc; IQ4_XS tops efficiency score
๐ง Deep Insight
Background and context from public sources โ not the original article. 7 sources cited.
๐ Enhanced Key Takeaways
- โขQwen3.5-35B-A3B employs a Gated Deltanet architecture with 75% linear attention layers, drastically reducing KV cache memory and enabling high throughput at long context lengths.[1]
- โขUnsloth's UD-Q4_K_XL and UD-Q3_K_XL quantizations of larger Qwen3.5-397B-A17B retain 80.5-80.7% accuracy on a 750-prompt benchmark, with only 3.5-4.3% relative error increase over BF16.[3]
- โขQwen3.5-35B-A3B activates only ~3B of its 35B total parameters per token via MoE routing, achieving up to 5x higher throughput than dense 27B models despite similar intelligence levels.[2]
๐ Competitor Analysisโธ Show
| Feature | Qwen3.5-35B-A3B (MoE) | Qwen3.5-27B (Dense) |
|---|---|---|
| Total Parameters | 35 Billion | 27 Billion |
| Active Parameters | ~3 Billion | 27 Billion |
| Throughput | 5x faster | Baseline |
| VRAM (Q4_K_M) | >16GB (needs IQ3/Q3) | Fits 16GB |
| Strengths | Speed/Efficiency | Reasoning/Accuracy |
๐ ๏ธ Technical Deep Dive
- โขGated Deltanet (linear attention) used in 75% of layers to minimize KV cache size and support long contexts with low memory overhead.[1]
- โขMoE routing activates ~3B parameters per token out of 35B total, balancing broad knowledge with compute efficiency akin to a 3B dense model.[2]
- โขUnsloth GGUF quantizations (e.g., UD-Q4_K_XL) optimized with iMatrix for Qwen3.5 series, enabling 3-bit runs on 192GB RAM or 4-bit on 256GB setups for larger variants.[3]
๐ฎ Future ImplicationsAI analysis grounded in cited sources
โณ Timeline
๐ Sources (7)
Factual claims are grounded in the sources below. Forward-looking analysis is AI-generated interpretation.
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