Can an M3 Pro 18GB Mac run Mistral Small 3 24B?
M3 Pro · 18 GB unified memory · 150 GB/s · MacBook Pro 14" (M3 Pro), MacBook Pro 16" (M3 Pro)
Mistral Small 3 24B needs about 16.2 GiB but an M3 Pro 18GB Mac has only ~15.0 GiB available for a model — you are 1.2 GiB short. macOS will swap to SSD and generation will crawl. There is a smaller quantisation that fits: see below.
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 | Tok/s | Fits? |
|---|---|---|---|---|
| FP16 | 44.0 GiB | 48.2 GiB | 3 | No |
| Q8_0 | 23.4 GiB | 26.6 GiB | 5 | No |
| Q6_K | 18.1 GiB | 21.1 GiB | 6 | No |
| Q5_K_M | 15.7 GiB | 18.5 GiB | 7 | No |
| Q4_K_M | 13.5 GiB | 16.2 GiB | 8 | No |
| Q3_K_M | 10.7 GiB | 13.3 GiB | 10 | Yes, but tight |
| Q2_K | 8.2 GiB | 10.7 GiB | 14 | Yes, 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.
| Context | KV cache | Total | FP16 KV | Q8 KV |
|---|---|---|---|---|
| 2K | 0.3 GiB | 15.0 GiB | No | Yes, but tight |
| 4K | 0.6 GiB | 15.4 GiB | No | No |
| 8K | 1.3 GiB | 16.2 GiB | No | No |
| 16K | 2.5 GiB | 17.7 GiB | No | No |
| 32K | 5.0 GiB | 20.8 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 Mistral Small 3 24B comfortably
The smallest configuration that handles it is the M2 24GB (MacBook Air 15" (M2)).
| Mac | Memory | Bandwidth | Tok/s |
|---|---|---|---|
| M2 24GB | 24 GB | 100 GB/s | 6 |
| M4 24GB | 24 GB | 120 GB/s | 7 |
| M4 Pro 24GB | 24 GB | 273 GB/s | 15 |
| M1 Max 32GB | 32 GB | 400 GB/s | 22 |
| M2 Max 32GB | 32 GB | 400 GB/s | 22 |
| M4 32GB | 32 GB | 120 GB/s | 7 |
| M3 Max 36GB | 36 GB | 300 GB/s | 17 |
| M4 Max 36GB | 36 GB | 410 GB/s | 23 |
| M4 Pro 48GB | 48 GB | 273 GB/s | 15 |
| M4 Max 48GB | 48 GB | 546 GB/s | 30 |
| M1 Max 64GB | 64 GB | 400 GB/s | 22 |
| M2 Ultra 64GB | 64 GB | 800 GB/s | 44 |
Common questions
- Can an M3 Pro 18GB Mac run Mistral Small 3 24B?
- No. At Q4_K_M it needs about 16.2 GiB, and an M3 Pro 18GB Mac has roughly 15.0 GiB available for a model after macOS takes its share.
- How fast is Mistral Small 3 24B on an Mac?
- Around 8 tokens per second. Token generation on Apple Silicon is limited by memory bandwidth, and this machine has 150 GB/s.
- How much memory does Mistral Small 3 24B need?
- 13.5 GiB for the weights at Q4_K_M, plus 1.3 GiB for an 8K-token KV cache and about 1.5 GiB of runtime overhead — 16.2 GiB in total.