Qwen · text · mixture of experts

Qwen3.5-35B-A3B-Base

Qwen/Qwen3.5-35B-A3B-Base

Qwen3.5-35B-A3B-Base at Q4_K_M is exactly 21,166,752,832 bytes (19.71 GiB / 21.17 GB) — an effective 4.710 bits per weight, not the nominal 4. Its KV cache at 32K is 0.63 GiB.

From the file· summed from 1 file(s)From the file· KV per layer
Parameters
36.0B
total, not active
Architecture
qwen35moe
40 layers
Context
262,144
native (config.json)
License
apache-2.0

Shipped quantizations

exact bytes, summed from published files
QuantSizeExact bytesEffective bpwTensorsPublisher
I1-IQ1_S6.80 GiB7,299,330,6881.624mradermacher
I1-IQ1_M7.51 GiB8,066,194,0481.795mradermacher
I1-IQ2_XXS8.70 GiB9,344,299,6482.079mradermacher
I1-IQ2_XS9.66 GiB10,369,405,5682.307mradermacher
I1-IQ2_S9.79 GiB10,514,854,5282.340mradermacher
I1-IQ2_M10.74 GiB11,537,339,0082.567mradermacher
I1-Q2_K_S11.21 GiB12,034,132,6082.678mradermacher
Q2_K11.94 GiB12,821,629,3122.853mradermacher
I1-Q2_K11.94 GiB12,821,629,5682.853mradermacher
I1-IQ3_XXS12.60 GiB13,533,319,8083.011mradermacher
I1-IQ3_XS13.43 GiB14,417,298,0483.208mradermacher
Q3_K_S14.14 GiB15,182,184,8323.378mradermacher
I1-Q3_K_S14.14 GiB15,182,185,0883.378mradermacher
I1-IQ3_S14.14 GiB15,183,577,7283.379mradermacher
I1-IQ3_M14.38 GiB15,440,519,8083.436mradermacher
Q3_K_M15.61 GiB16,760,832,3843.730mradermacher
I1-Q3_K_M15.61 GiB16,760,832,6403.730mradermacher
Q3_K_L16.81 GiB18,052,415,8724.017mradermacher
I1-Q3_K_L16.81 GiB18,052,416,1284.017mradermacher
I1-IQ4_XS17.37 GiB18,650,135,1684.150mradermacher
IQ4_XS17.57 GiB18,860,669,3124.197mradermacher
Q4_018.36 GiB19,715,048,5124.387Azure99
I1-Q4_018.44 GiB19,799,267,9684.406mradermacher
Q4_K_S18.52 GiB19,884,005,7604.425mradermacher
I1-Q4_K_S18.52 GiB19,884,006,0164.425mradermacher
Q4_K_S18.52 GiB19,889,898,5604.426Azure99
Q4_K_M19.71 GiB21,166,752,8324.710Azure99
Q4_K_M19.72 GiB21,169,117,5684.711mradermacher
I1-Q4_K_M19.72 GiB21,169,117,8244.711mradermacher
I1-Q4_120.35 GiB21,848,169,0884.862mradermacher
Q5_K_S22.33 GiB23,981,278,2725.336Azure99
Q5_K_S22.33 GiB23,981,283,7125.336mradermacher
I1-Q5_K_S22.33 GiB23,981,283,9685.336mradermacher
Q5_K_M23.03 GiB24,729,125,9525.503Azure99
Q5_K_M23.06 GiB24,764,782,9765.511mradermacher
I1-Q5_K_M23.06 GiB24,764,783,2325.511mradermacher
Q6_K26.56 GiB28,514,147,3926.345Azure99
Q6_K26.56 GiB28,514,152,8326.345mradermacher
I1-Q6_K26.56 GiB28,514,153,0886.345mradermacher
Q8_034.37 GiB36,903,134,2728.212Azure99

KV cache by context

computed per layer
ContextKV cache (f16)Flat formulaOverstated byFull / windowed / recurrent
4,0960.08 GiB0.31 GiB4.00×10 / 0 / 30
8,1920.16 GiB0.63 GiB4.00×10 / 0 / 30
16,3840.31 GiB1.25 GiB4.00×10 / 0 / 30
32,7680.63 GiB2.50 GiB4.00×10 / 0 / 30
65,5361.25 GiB5.00 GiB4.00×10 / 0 / 30
131,0722.50 GiB10.00 GiB4.00×10 / 0 / 30

30 of 40 layers use linear attention, which keeps a fixed-size recurrent state instead of a per-token cache. Those layers do not grow with context at all — treating them as ordinary attention, as a flat formula does, overstates this model's cache by roughly 4.0× at long context.

Compare with

same modality, comparable size

Will it run on your card?

full quant x context sweep

Why other calculators give a different number

A parameters × bits ÷ 8 estimate puts Q4_K_M at roughly 18.83 GiB. The real file is 19.71 GiB, because a quantization is a mixture and some tensors are always kept at higher precision.

Architecture

from config.json
Layers
40
Attention heads
16
KV heads
2
Head dim
256
Hidden size
2048
Vocab
248,320
Sliding window
none
SWA period
MLA
no
Experts
256
Experts per token
8
use_sliding_window

Questions people ask

How much VRAM does Qwen3.5-35B-A3B-Base need?
Q4_K_M is exactly 21,166,752,832 bytes (19.71 GiB) in weights. Add the KV cache, which depends on your context length, plus roughly half a gigabyte of runtime overhead.
How large is Qwen3.5-35B-A3B-Base's KV cache?
0.63 GiB at 32K context with an f16 cache, computed per layer. Quantizing the cache to q8_0 roughly halves it, which is often the difference between a context length fitting and not.
Is Qwen3.5-35B-A3B-Base a mixture-of-experts model?
Yes — 256 experts, 8 routed per token. Every expert must be resident, but only the routed ones are read per token, which is why its memory requirement and its speed behave very differently.
Which quantization of Qwen3.5-35B-A3B-Base should I use?
Q4_K_M is the usual default. Pick the largest quantization that fits your card at the context you actually need — the table above gives exact sizes for every one published.