Build It

How Much Storage You Actually Need

Model files are bigger than most people expect. Here is how to size storage correctly and why drive speed matters as much as capacity.

10 minute read

Why storage catches people off guard

Most hardware guides for local AI talk about RAM and CPU and barely mention the drive. That's a mistake - model files are large, you'll want to try more than one, and drive speed directly affects how long you wait every time a model loads into memory.

This isn't a huge line item compared to RAM or a GPU, but getting it wrong means either running out of space faster than expected or sitting through slow model loads on every restart.

Sizing it correctly

The rough rule of thumb: a model at common quantization needs about as many gigabytes as it has billions of parameters, give or take. A 7-8B model runs 4-5GB. A 13B model runs 7-8GB. That adds up fast once you're trying a few different models to compare.

  • 256GB: the bare minimum - enough for a handful of smaller models and not much else
  • 512GB: a comfortable working size for trying multiple models plus normal OS and app usage
  • 1TB+: only worth it if you plan to keep several larger models on hand at once
Good default: 512GB gives real room to experiment without thinking about it constantly, and most mini PCs offer it as a reasonable upgrade over the base 256GB configuration.

Speed matters as much as size

An NVMe SSD and a SATA SSD can list the exact same capacity and cost close to the same amount, but they are not equivalent for this use case. NVMe drives connect directly over faster lanes and load a multi-gigabyte model file into memory noticeably quicker than SATA.

This matters most the first time you switch models in a session - Ollama has to read that model off disk before it can respond. On a slow drive, that pause is very noticeable. On NVMe, it's barely there.

Check before you buy: some budget mini PCs technically support NVMe but ship with a slower SATA-protocol M.2 drive by default. Confirm the actual drive spec, not just the physical slot type.

What actually goes wrong

The drive fills up faster than expected

This usually isn't the model files themselves - it's trying several models "just to see," forgetting to remove the ones you didn't keep using. Check what's actually installed:

ollama list

Remove anything you're not using with ollama rm <model-name> - it's a one-line re-download if you want it back later.

Model loading feels slow even with a "fast" drive

Double check the drive is actually running in NVMe mode and not accidentally configured or throttled down. This is more common on budget hardware than people expect, and it's worth confirming once rather than assuming.

Common questions

Can I run local AI off an external drive?
You can, but expect a real speed hit unless it's a fast external NVMe drive over USB-C. A spinning external hard drive will make model loading painfully slow.
Do I need to keep every model I try?
No. Models are easy to re-download with one command, so it is fine to delete ones you are not actively using and pull them again later if you want them back.

Go deeper

This guide covers one solid path. Here's where to go if you want something different.

Mini PC Lab Detailed drive benchmarks across specific mini PC models, if you want exact numbers before buying. r/LocalLLaMA Real-world reports on which budget mini PCs quietly ship slower storage than advertised.

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