google · vision language

medgemma-1.5-4b-it

google/medgemma-1.5-4b-it

medgemma-1.5-4b-it at Q4_K_M is exactly 2,489,894,624 bytes (2.32 GiB / 2.49 GB) — an effective 4.632 bits per weight, not the nominal 4. Its KV cache at 32K is 0.79 GiB, not the 4.25 GiB a flat formula predicts.

From the file· summed from 1 file(s)From the file· KV from mirror (mirror:unsloth/medgemma-1.5-4b-it)
Parameters
4.3B
Architecture
gemma3
34 layers
Context
131,072
native (config.json)
License
other

Shipped quantizations

exact bytes, summed from published files
QuantSizeExact bytesEffective bpwTensorsPublisher
UD-IQ1_S1.10 GiB1,183,392,5762.202unsloth
UD-IQ1_M1.16 GiB1,242,579,7762.312unsloth
UD-IQ2_XXS1.25 GiB1,344,119,6162.501unsloth
UD-IQ2_M1.46 GiB1,567,884,0962.917unsloth
UD-IQ3_XXS1.59 GiB1,710,752,5763.183unsloth
Q2_K1.61 GiB1,729,165,0243.217mradermacher
Q2_K_L1.61 GiB1,729,165,3763.217unsloth
Q2_K1.61 GiB1,729,165,3763.217unsloth
Q3_K_S1.80 GiB1,937,364,7043.604mradermacher
Q3_K_S1.80 GiB1,937,365,0563.604unsloth
Q3_K_M1.95 GiB2,098,460,3843.904mradermacher
Q3_K_M1.95 GiB2,098,460,7363.904unsloth
Q3_K_L2.08 GiB2,236,085,9844.160mradermacher
IQ4_XS2.11 GiB2,263,242,8164.211unsloth
IQ4_XS2.12 GiB2,279,626,4644.241mradermacher
IQ4_NL2.20 GiB2,363,512,8964.397unsloth
Q4_02.21 GiB2,370,066,4964.409unsloth
Q4_K_S2.21 GiB2,377,930,4644.424mradermacher
Q4_K_S2.21 GiB2,377,930,8164.424unsloth
Q4_K_M2.32 GiB2,489,894,6244.632mradermacher
Q4_K_M2.32 GiB2,489,894,9764.632unsloth
Q4_12.39 GiB2,564,053,0564.770unsloth
Q5_K_S2.57 GiB2,764,592,8645.143mradermacher
Q5_K_S2.57 GiB2,764,593,2165.143unsloth
Q5_K_M2.64 GiB2,829,698,7845.264mradermacher
Q5_K_M2.64 GiB2,829,699,1365.264unsloth
Q6_K2.97 GiB3,190,740,7045.936mradermacher
Q6_K2.97 GiB3,190,741,0565.936unsloth
Q8_03.85 GiB4,130,402,7847.684mradermacher
Q8_03.85 GiB4,130,403,1367.684unsloth
F167.23 GiB7,767,804,38414.451mradermacher
BF167.23 GiB7,767,804,48014.451unsloth

KV cache by context

computed per layer — this model uses sliding-window attention
ContextKV cache (f16)Flat formulaOverstated byFull / windowed / recurrent
4,0960.25 GiB0.53 GiB2.14×5 / 29 / 0
8,1920.33 GiB1.06 GiB3.26×5 / 29 / 0
16,3840.48 GiB2.13 GiB4.40×5 / 29 / 0
32,7680.79 GiB4.25 GiB5.35×5 / 29 / 0
65,5361.42 GiB8.50 GiB5.99×5 / 29 / 0
131,0722.67 GiB17.00 GiB6.37×5 / 29 / 0

29 of 34 layers cache only a 1,024-token window rather than the full context, on a period of 6. Figures assume the default configuration; --swa-full disables the saving entirely.

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 2.25 GiB. The real file is 2.32 GiB, because a quantization is a mixture and some tensors are always kept at higher precision. The larger discrepancy is the cache: a flat formula gives 4.25 GiB at 32K context where the real figure is 0.79 GiB, because most of this model's layers cache a fixed window rather than the whole context.

Architecture

from mirror:unsloth/medgemma-1.5-4b-it
Layers
34
Attention heads
8
KV heads
4
Head dim
256
Hidden size
2560
Vocab
262,208
Sliding window
1024
SWA period
6
MLA
no
Experts
Experts per token
use_sliding_window

Questions people ask

How much VRAM does medgemma-1.5-4b-it need?
Q4_K_M is exactly 2,489,894,624 bytes (2.32 GiB) in weights. Add the KV cache, which depends on your context length, plus roughly half a gigabyte of runtime overhead.
How large is medgemma-1.5-4b-it's KV cache?
0.79 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.
Which quantization of medgemma-1.5-4b-it 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.