Short answer
A PC graphics card is much faster for any model that fits inside its memory, and nearly all AI software targets it first. A Mac loads far larger models for the money and draws less power, at lower speed, so the choice comes down to whether your models fit in 16 to 32 GB and whether you plan to train as well as run them.
Follow-up question Which one should a beginner choose?
The two designs make opposite trade-offs. A graphics card has a small pool of extremely fast memory soldered next to a powerful processor. An Apple silicon Mac has one large pool of moderately fast memory shared by everything. Neither wins outright, and the right answer depends on the size of the model you want to run.
The 2024 hardware guide asked whether a large-memory Mac is enough. Two years on, there are better numbers for answering it.
The hardware side by side
| RTX 5090 | RTX PRO 6000 | Mac Studio M5 Max | Mac Studio M5 Ultra | |
|---|---|---|---|---|
| Fast memory | 32 GB | 96 GB | Up to 128 GB | Up to 512 GB |
| Bandwidth | Not listed on its spec page | 1,792 GB/s | 460 or 614 GB/s | 1.2 TB/s |
| Peak power | 575 W for the card | 600 W for the card | 200 W for the whole computer | 385 W for the whole computer |
| Upgrade later | Swap or add cards | Swap or add cards | No | No |
The specifications are the makers' own (RTX 5090, RTX PRO 6000, Mac Studio, Apple power figures). Note the card figures cover only the card, and a PC around it draws more.
What the benchmarks show
The most useful Apple numbers come from the llama.cpp project, which keeps a public table with the exact commit and command, so that anyone can repeat the test. It uses LLaMA 7B, an older small model, compressed to 4 bits:
| Chip | Bandwidth | Tokens per second |
|---|---|---|
| M4 | 120 GB/s | 24 |
| M6 | 170 GB/s | 36 |
| M5 Pro | 307 GB/s | 66 |
| M4 Max (40-core GPU) | 546 GB/s | 83 |
| M5 Max (40-core GPU) | 614 GB/s | 120 |
| M5 Ultra (80-core GPU) | 1,228 GB/s | 179 |
The pattern is plain: more bandwidth brings more speed, though doubling it from Max to Ultra added about 50% here.
For graphics cards, LMSYS published a comparison in October 2025 using gpt-oss-20b in Ollama:
| Machine | Writing speed | Reading speed (prompt) |
|---|---|---|
| RTX PRO 6000 | 215 tokens/s | 10,108 tokens/s |
| RTX 5090 | 205 tokens/s | 8,519 tokens/s |
| DGX Spark (273 GB/s shared memory) | 49.7 tokens/s | 2,053 tokens/s |
The two tables use different models and software, so do not compare a row in one with a row in the other. What they do show together is the shape of each option. A card's memory is several times faster than a typical shared pool, and a good card is about four times faster than the Spark on the same test. LMSYS's figures are a year old, and it warned that early software could date them.
Reading speed matters more than it first appears. When an agent loads a large codebase, the model has to process all of it before writing a word. On a shared-memory laptop, Microsoft's own test of a 137-billion-parameter model implies about 71 seconds for a cold 64,000-token prompt.
The software gap
For running a model, the gap has closed. Ollama, LM Studio and llama.cpp all work well on a Mac, and Apple's own MLX LM runs models and does LoRA fine-tuning (adjusting an existing model with a small add-on) on Apple silicon.
Beyond that, NVIDIA still leads. vLLM, a server built for many simultaneous users, ships pre-compiled for CUDA and supports AMD through ROCm, while on Apple silicon it relies on vLLM-Metal, a community-maintained plugin. Most training tutorials, research code and new tools assume CUDA. If you plan to train a small model of your own, a Mac will make you solve problems others have not met.
Windows has its own catch: vLLM does not support it natively, so serving on a Windows PC usually means WSL, the Linux layer inside Windows, or a tool such as Ollama instead.
A decision table
| You want to | Better fit | Why |
|---|---|---|
| Run models under about 30 GB, quickly | PC with a graphics card | Highest speed once it fits |
| Run models of 60 GB or more on one machine | Mac, or a shared-memory desktop | GeForce stops at 32 GB, and the 96 GB RTX PRO 6000 listed at US$16,000 on October 28 |
| Train or fine-tune seriously | PC with NVIDIA | Software assumes CUDA |
| Keep a machine on all day | Mac | 7 to 9 W idle, and low peak power |
| Upgrade in stages | PC | Add or swap cards |
| Serve several people at once | PC with NVIDIA, on Linux | vLLM targets this setup first |
Try it: If you own an Apple silicon Mac, follow the instructions in llama.cpp discussion 4167 and run its benchmark. Compare your result with the table above: being well below your chip's row usually means other apps are taking memory or bandwidth.
Which one should a beginner choose?
Whichever you already own. Both run the same open models with the same free tools, and you learn the same things on either. A Mac with 16 GB or a PC with an 8 GB card is enough to find out whether local AI is useful to you before spending anything.
If you are buying specifically for this, look at your main goal. Choose a Mac if you want a simple, low-power machine that also handles bigger models, and you mostly run them rather than train them. Choose a PC with an NVIDIA card if you also want to train, already use a Windows or Linux desktop, or care most about speed on models that fit. With graphics card prices where they are in late 2026, compare the whole system price for the memory you need, using the dated tiers in the buying guide.
Sources
- Performance of llama.cpp on Apple Silicon M-series (Discussion 4167) — ggml-org (GitHub)
- NVIDIA DGX Spark In-Depth Review: A New Standard for Local AI Inference — LMSYS Org, October 13, 2025
- GPU installation, vLLM documentation — vLLM project
Sources for the articles linked in the text
Each linked article has its own page, with its sources and its date.
- What is llama.cpp, and how can a large language model run on a laptop?
- llama.cpp README (commit 73c6ed5, 10 March 2023) — GitHub (Georgi Gerganov), March 10, 2023
- llama.cpp README (commit da1a4ff, 11 March 2023) — GitHub (Georgi Gerganov), March 11, 2023
- Large language models are having their Stable Diffusion moment — Simon Willison's Weblog, March 11, 2023
- What is Ollama, and how does it let you run AI models on your own Mac?
- Ollama repository: README, models.json and website page (commit b43ddd8, 8 July 2023) — GitHub (jmorganca/ollama), July 8, 2023
- Ollama v0.0.1 release — GitHub (jmorganca/ollama), July 8, 2023
From the Guide to Artificial Intelligence, by Robert Scales, published by Holistic Hybrid Inc. Share and adapt it under CC BY-NC-SA 4.0: credit the guide, link to https://guidetoartificialintelligence.com/en/learn/mac-vs-pc-gpu-local-ai/, no commercial use without permission, and keep the same licence.