WizardLM 13B needs ~48.7 GB VRAM. Mac Studio M3 Ultra 256GB has 184.3 GB. With Q4_K_M quantization, expect ~70 tok/s.
Operating mode
Interactive favors responsiveness, while light API and scale-out lean harder on serving readiness. The fit stays the same, but the recommendation lens changes.
Current mode
Balanced
Balanced for general local use. Keeps the ranking neutral across personal and serving workflows.
Select quantization to explore
Fit status
Runs well
Decode
70.2 tok/s
TTFT
2757 ms
Safe context
8K
Memory
48.7 GB / 184.3 GB
This setup is broadly balanced for this model.
Shared-memory contention still exists
The OS, browser, and inference runtime all compete for the same physical memory pool, so real-world headroom is less forgiving than raw capacity suggests.
| Workload | Grade | Fit | Decode | TTFT | Context |
|---|---|---|---|---|---|
| Chat | B | Runs well | 70.2 tok/s | 1504 ms | 8K |
| Coding | B | Runs well | 70.2 tok/s | 2757 ms | 8K |
| Agentic Coding | B | Runs well | 70.2 tok/s | 4010 ms | 8K |
| Reasoning | B | Runs well | 70.2 tok/s | 3258 ms | 8K |
| RAG | B | Runs well | 70.2 tok/s | 5012 ms | 8K |
How WizardLM 13B (13B params) fits at each quantization level on Mac Studio M3 Ultra 256GB (184.3 GB usable).
| Quant | Bits | VRAM | Quality | Fit |
|---|---|---|---|---|
Q2_K | 2 | 5.1 GB | Low | B58 |
Q3_K_S | 3 | 6.4 GB | Low | B58 |
NVFP4 | 4 | 7.3 GB | Medium | B58 |
Q4_K_M | 4 | 7.9 GB | Medium | B58 |
Q5_K_M | 5 | 9.4 GB | High | B58 |
Q6_K | 6 | 10.7 GB | High | B58 |
Q8_0 | 8 | 13.9 GB | Very High | B58 |
F16Best for your GPU | 16 | 26.7 GB | Maximum | B59 |
Copy-paste commands to run WizardLM 13B on your machine.
Run
lms load WizardLM-13B-V1.0 && lms server startYes, Mac Studio M3 Ultra 256GB can run WizardLM 13B with a B grade (Runs well). Expected decode speed: 70.2 tok/s.
WizardLM 13B (13B parameters) requires approximately 48.7 GB of memory with Q4_K_M quantization.
The recommended quantization for WizardLM 13B is Q4_K_M, which balances quality and memory efficiency.
On Mac Studio M3 Ultra 256GB, WizardLM 13B achieves approximately 70.2 tokens per second decode speed with a time-to-first-token of 2757ms using Q4_K_M quantization.
For coding workloads, WizardLM 13B on Mac Studio M3 Ultra 256GB receives a B grade with 70.2 tok/s and 8K context.
On Mac Studio M3 Ultra 256GB, WizardLM 13B can safely use up to 8K tokens of context. The model's official context limit is 8K, but available memory constrains the safe maximum.
Not always. Mac Studio M3 Ultra 256GB can often fit larger models thanks to unified memory, but a discrete GPU with dedicated high-bandwidth VRAM may still decode faster once the model fits. For this combination, the important distinction is capacity versus sustained throughput.
Paste this snippet into any page to show a live fit card.
<iframe src="https://willitrunai.com/embed/wizardlm-13b-on-m3-ultra-256gb" width="400" height="180" frameborder="0" style="border:none;border-radius:12px;overflow:hidden;" title="Will It Run AI — fit result"></iframe>
Preview: