Side-by-side simulation · recommended settings
M3 Ultra vs M5 Ultra 512GB: Upgrade for local LLMs?
Both are 512GB configurations, so replacement is about running the same model faster. Update the M3 Ultra's runtime first, then compare the waiting time saved by M5 Ultra.
Choose devices and a model
Expand comparison settings
Same 117output tokens. Only evidence-qualified acceleration is selected automatically; runtime formats are shown on each device.
Left
ReadyStudio M3 Ultra 512GB
Press Start above to generate the same answer on both devices.
Right
ReadyStudio M5 Ultra 512GB
Press Start above to generate the same answer on both devices.
With these settings, Studio M5 Ultra 512GB finishes the full answer About 6.8× faster.
Compare from input processing to completion of 117 token response.
Which one fits my needs?
Answer completion
Studio M5 Ultra 512GB
At the estimate midpoint, it finishes the same answer about 6.8× faster.
Prompt processing
Studio M5 Ultra 512GB
The estimated input-processing midpoint is higher at 2,270 tok/s.
Image and video generation
Check the media model
LLM speed does not tell you media-generation performance. Choose the image or video model and resolution separately.
Runtime
Settings for your hardware
MLX 4-bit / oMLX 0.7.0 (4d4f5a28) · mlx-lm 94cdcae · mlx 0.32.2 · native kernels · Lightning MTP on. When runtime paths differ, the speed gap also includes software and model-format differences.
Estimated power draw
Studio M3 Ultra 512GB
Estimated LLM power draw is lower at about 230 W. Noise and physical size need a separate check.
Local pricing
Studio M5 Ultra 512GB costs about 1,348 × KRW 10,000 more at the reference-price midpoint, with an estimated answer time about 85% shorter.
Before choosing hardware
| Measure | Studio M3 Ultra 512GB | Studio M5 Ultra 512GB |
|---|---|---|
| Available fast memory | 480GB | 480GB |
| Memory bandwidth | 819GB/s | 1200GB/s |
| Estimated total time | 25 s | 3.6 s |
| Estimated sustained LLM load | about 230W | about 330W |
| Korean price range (KRW) | 2,400–2,600 × KRW 10,000 | 3,805–3,890 × KRW 10,000 |
Estimated ranges for one user. Multi-GPU and multi-device results depend on the runtime and interconnect.
Update the existing Mac's runtime first
An older engine on M3 Ultra may leave room for shorter waits without new hardware. Match the recommended engine, quantization and acceleration before comparing. This separates gains from a new chip from those achieved by updating software.
Run long prefill and long answers separately
For frequent reports, full mode with long input matters. For code or long drafts, compare continuing answer speed. Decide which stage must improve to keep work flowing, then weigh it against the new machine's cost.
Distinguish SSD loading from inference waits
Initial model loading and waiting on every question need different improvements. For slow initial loading, check residency and storage location. For repeated documents, examine cache settings. Keep these waiting stages separate when comparing the new Mac's SSD and chip.