How fast is DeepSeek V4.1 Flash on an Mac?

Around 0 tokens per second. Token generation on Apple Silicon is limited by memory bandwidth, and this machine has 150 GB/s.

How much memory does DeepSeek V4.1 Flash need?

435.4 GiB for the weights at Q4_K_M, plus 0.6 GiB for an 8K-token KV cache and about 22.6 GiB of runtime overhead — 458.6 GiB in total.

Home › DeepSeek V4.1 Flash › M3 Pro 18GB

Can an M3 Pro 18GB Mac run DeepSeek V4.1 Flash?

M3 Pro · 18 GB unified memory · 150 GB/s · MacBook Pro 14" (M3 Pro), MacBook Pro 16" (M3 Pro)

No — not at Q4_K_M.

DeepSeek V4.1 Flash needs about 458.6 GiB but an M3 Pro 18GB Mac has only ~15.0 GiB available for a model — you are 443.6 GiB short. macOS will swap to SSD and generation will crawl.

Weights

435.4 GiB

763.21B params @ Q4_K_M

KV cache

0.6 GiB

8K context, FP16

Overhead

22.6 GiB

runtime + activations

Total needed

458.6 GiB

of ~15.0 GiB usable

Est. speed

0 tok/s

150 GB/s bandwidth

Max context

n/a

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 — the KV cache grows with every token in your context.

Quantisation	Weights	Total	Fits?
FP16	1421.6 GiB	1494.1 GiB	No
Q8_0	755.2 GiB	794.4 GiB	No
Q6_K	586.4 GiB	617.2 GiB	No
Q5_K_M	506.4 GiB	533.2 GiB	No
Q4_K_M	435.4 GiB	458.6 GiB	No
Q3_K_M	346.5 GiB	365.3 GiB	No
Q2_K	266.5 GiB	281.3 GiB	No

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.

Context	KV cache	Total	FP16 KV	Q8 KV
2K	0.2 GiB	457.9 GiB	No	No
4K	0.3 GiB	458.1 GiB	No	No
8K	0.6 GiB	458.6 GiB	No	No
16K	1.3 GiB	459.5 GiB	No	No
32K	2.5 GiB	461.3 GiB	No	No
128K	10.0 GiB	472.4 GiB	No	No

What to run instead on an M3 Pro 18GB Mac

These are the largest models that fit comfortably on this machine at Q4_K_M with an 8K context.

Model	Size	Total	Tok/s
DeepSeek-R1-Distill-Qwen-14B	14.8B	11.2 GiB	13	Yes, comfortably
Qwen2.5 14B	14.8B	11.2 GiB	13	Yes, comfortably
Qwen2.5-Coder 14B	14.8B	11.2 GiB	13	Yes, comfortably
Qwen3 14B	14.8B	10.9 GiB	13	Yes, comfortably
Phi-4 14B	14.7B	11.2 GiB	13	Yes, comfortably
Gemma 3 12B	12.2B	11.1 GiB	16	Yes, comfortably

Macs that run DeepSeek V4.1 Flash

No Apple Silicon configuration in our list runs DeepSeek V4.1 Flash comfortably at Q4_K_M with an 8K context. This one needs a multi-GPU server.

Common questions

Can an M3 Pro 18GB Mac run DeepSeek V4.1 Flash?: No. At Q4_K_M it needs about 458.6 GiB, and an M3 Pro 18GB Mac has roughly 15.0 GiB available for a model after macOS takes its share.
How fast is DeepSeek V4.1 Flash on an Mac?: Around 0 tokens per second. Token generation on Apple Silicon is limited by memory bandwidth, and this machine has 150 GB/s.
How much memory does DeepSeek V4.1 Flash need?: 435.4 GiB for the weights at Q4_K_M, plus 0.6 GiB for an 8K-token KV cache and about 22.6 GiB of runtime overhead — 458.6 GiB in total.