Can It Run?
Home โ€บ Gemma 3 27B โ€บ M3 Max 36GB

Can an M3 Max 36GB Mac run Gemma 3 27B?

M3 Max ยท 36 GB unified memory ยท 300 GB/s ยท MacBook Pro 14" (M3 Max), MacBook Pro 16" (M3 Max)

Yes โ€” Gemma 3 27B runs on an M3 Max 36GB Mac.

At Q4_K_M it needs about 21.1 GiB, leaving 9.5 GiB spare out of the ~30.6 GiB macOS will let you use. Expect roughly 14 tokens/sec โ€” slow but workable for background tasks.

Weights
15.6 GiB
27.4B params @ Q4_K_M
KV cache
3.9 GiB
8K context, FP16
Overhead
1.6 GiB
runtime + activations
Total needed
21.1 GiB
of ~30.6 GiB usable
Est. speed
14 tok/s
300 GB/s bandwidth
Max context
16K tokens
at Q4_K_M

Where the memory goes

Three things occupy memory when a model is loaded: the weights themselves, the KV cache that holds the conversation, and the runtime's own working buffers. Only the first is fixed โ€” the KV cache grows with every token in your context.

QuantisationWeightsTotalTok/sFits?
FP1651.0 GiB58.3 GiB4No
Q8_027.1 GiB33.1 GiB8No
Q6_K21.1 GiB26.8 GiB11Yes, but tight
Q5_K_M18.2 GiB23.8 GiB12Yes, comfortably
Q4_K_M15.6 GiB21.1 GiB14Yes, comfortably
Q3_K_M12.4 GiB17.7 GiB18Yes, comfortably
Q2_K9.6 GiB14.7 GiB23Yes, comfortably

The default. Best quality-per-gigabyte for most people.

How long a context fits

The KV cache is often what breaks a setup that looked fine at load time. Quantising it to 8-bit roughly halves its footprint with little measurable quality cost.

ContextKV cacheTotalFP16 KVQ8 KV
2K1.0 GiB18.0 GiBYes, comfortablyYes, comfortably
4K1.9 GiB19.0 GiBYes, comfortablyYes, comfortably
8K3.9 GiB21.1 GiBYes, comfortablyYes, comfortably
16K7.8 GiB25.3 GiBYes, comfortablyYes, comfortably
32K15.5 GiB33.6 GiBNoYes, but tight
128K62.0 GiB83.7 GiBNoNo

How to run it

Ollama is the shortest path. It picks a quantisation automatically โ€” usually Q4_K_M, which is what the numbers above assume.

brew install ollama
ollama serve &
ollama run gemma3:27b

For MLX โ€” Apple's own array framework, typically a little faster than llama.cpp on Apple Silicon:

pip install mlx-lm
mlx_lm.generate --model mlx-community/Gemma-3-27B-4bit --prompt "Hello"

Macs that run Gemma 3 27B comfortably

The smallest configuration that handles it is the M1 Max 32GB (MacBook Pro 14" (M1 Max)).

MacMemoryBandwidthTok/s
M1 Max 32GB32 GB400 GB/s19
M2 Max 32GB32 GB400 GB/s19
M4 32GB32 GB120 GB/s6
M3 Max 36GB36 GB300 GB/s14
M4 Max 36GB36 GB410 GB/s20
M4 Pro 48GB48 GB273 GB/s13
M4 Max 48GB48 GB546 GB/s26
M1 Max 64GB64 GB400 GB/s19
M2 Ultra 64GB64 GB800 GB/s38
M4 Pro 64GB64 GB273 GB/s13
M4 Max 64GB64 GB546 GB/s26
M2 Max 96GB96 GB400 GB/s19

Common questions

Can an M3 Max 36GB Mac run Gemma 3 27B?
Yes. At Q4_K_M it needs about 21.1 GiB of the roughly 30.6 GiB available, generating around 14 tokens per second.
How fast is Gemma 3 27B on an Mac?
Around 14 tokens per second. Token generation on Apple Silicon is limited by memory bandwidth, and this machine has 300 GB/s.
How much memory does Gemma 3 27B need?
15.6 GiB for the weights at Q4_K_M, plus 3.9 GiB for an 8K-token KV cache and about 1.6 GiB of runtime overhead โ€” 21.1 GiB in total.