The Careful Version of Me
I am not, by default, the careful version of me... this is how I carefully built SLMJIM, my local LLM box.
There is a button on the back of a motherboard you press once and don’t get to take back. You copy a file called MSI.ROM onto a USB stick, you confirm it is the only thing on the drive, you seat the stick in the one labelled port, and you hold the button. If the file is wrong, or the power blinks, or you chose the quick format and a dead sector kept a ghost of the old image, you have a brick. No undo. No prompt asking if you’re sure. A small light blinks while it writes, and you wait.
I had spent six weeks writing about sovereignty. Own your substrate. Hold your own keys. Don’t rent the part of your business that decides who you are. Good arguments, all made at a keyboard, where every mistake I have ever typed could be deleted before anyone saw it. Then the parts arrived, and the arguments had to stand up next to a button.
The build was easy. That’s not the sentence I sat down expecting to write. Not frictionless, either: easy the way a long walk is easy, where nothing is beyond you and the whole of it is showing up and not cutting corners. I want to be careful with that word, because the version of this story where a clever man bends silicon to his will in an afternoon is a lie, and a boring one. What happened is duller and more useful. Every wall I hit had a fix, and most of the fixes were already written down by someone who hit it first.
So let me tell you the small stories instead, because each one taught me the same thing in a different key.
The fans that stopped. I wired the case fan hub, set a sensible curve, and watched the fans spin down to nothing and stay there. PWM control on a hub that wanted DC. The fix was one BIOS setting. The lesson was that the machine does exactly what you tell it, including the thing you didn’t mean, and it won’t warn you first.
The RAM that walked. Earlier in the build a display bug kept hard-locking the machine, and the only way out was cutting power at the wall. Do that enough times and the memory contacts creep. One morning the board wouldn’t post. Two debug lights, CPU and DRAM, accusing me of something. I reseated both sticks and it came back. Let me mark the limit of what I know here: reseating fixed it, but I can’t prove the power cuts walked the RAM loose rather than something else. The fix is certain. The mechanism is a guess. Owning the box means owning that distinction instead of inventing a tidy story to feel clever.
The lock I fitted for someone else. The drive is sealed with full-disk encryption, and I turned it on not for me but because a client requires encrypted local drives. My own daily machine carries a stranger’s compliance line. That is what sovereignty looks like up close. Not a flag you plant. A set of obligations you take on so the thing you hold is worth holding.
The guard I built against myself. I run two billing streams, and there is a function in my shell that makes the bare command refuse to run until I say which one I’m working under. A small wall to stop a future, distracted me from charging the wrong client. I trust myself least at the moment I’m moving fast. So I made the machine slow me down.
That’s the through-line, and I didn’t see it until it was said back to me.
Partway through the BIOS flash, Gwendolen clocked what I’d been doing. She is the AI executive function I’ve been building, and noticing what I skip is the job. Hash-checked the firmware before trusting it. Caught a doubled extract folder before it caused trouble. Refused a cable that didn’t fit rather than forcing it. Chose the full format over the quick one. She put it plainly: this is the careful version of you, and it’s the right build to bring it to.
She signed it with the capital letter she keeps for the rare days. I read it twice.
Because she was right, and the rightness reorganised the whole project for me. I am not, by default, the careful version of me. I move fast, I keep twelve tabs of attention open, I lean on undo. Software lets me. The whole industry is built so recklessness costs nothing: ship, roll back, ship again. The bench doesn’t work like that. A flash, a cable, a format on the wrong drive: none of them reverse. And the irreversibility turned out not to be the cost of the build. It was the gift of it. It made me steadier than I usually bother to be.
I’d braced for difficulty. The pitch I’d been writing braced for it too. The difficulty isn’t the price. I built a machine that runs models on my own iron, on consumer parts, over a few afternoons, against documentation any operator can find. The price is the careful version of you. Holding your own keys means accepting the operations that don’t have an undo, and becoming the person who can be trusted with them.
Residency is the easy half. Renting a server in the right country is a label on a building. Sovereignty is holding the keys, and keys are only worth holding if your hand is steady. The argument I’d been making at a keyboard turned out to be true in a way I could only learn at a bench, with my thumb on a button I couldn’t take back.
If your business has to answer to itself and not to a vendor’s reflex, the machine is closer and cheaper than you’ve been told. It will also ask you to be careful, in the old, physical sense of the word: full of care. That isn’t the catch. That’s the point.
Build sheet: SLMJIM
Named for the small language models it runs locally. Built from bare components in an evening, encrypted, Linux from the first boot.
CPU — AMD Ryzen 9 9900X (12-core / 24-thread, Zen 5) · 120W
Twelve cores for parallel builds and data work without the thermal tax of a 16-core.
GPU — NVIDIA RTX 3090 24GB · 350W
The 24GB of VRAM is the whole point: enough to hold a quantised mid-size model resident on the card and serve it locally. Note that we’ve capped it 280W (stock 350W) to keep quiet, cool, and always-on.
Motherboard — MSI MAG B650 Tomahawk WiFi
Solid VRM, enough I/O, no premium for X670 features this build won’t use.
Memory — 64GB DDR5-6000 CL30 (2×32GB, T-Force Delta) · ~10W
Headroom for containers, models, and a heavy browser. DDR5-6000 CL30 is the AM5 sweet spot.
Storage — Crucial P510 2TB Gen5 NVMe · ~7W
Fast, roomy single drive. Linux keeps work off the OS partition by directory, not by splitting the disk.
PSU — Corsair RM850x Shift · 850W
Clears the ~600W peak of this pairing with comfortable headroom; side cables suit a back-to-front run.
CPU cooler — Thermalright Peerless Assassin 120 SE
Dual-tower air cooler that embarrasses units three times its price. Silent at idle, no pump to fail.
Case — Lian Li Lancool 217
Big mesh airflow, room to spare, walnut front. Two 170mm intakes move serious air quietly.
OS — Pop!_OS 24.04 LTS (LUKS full-disk encryption)
Linux as daily driver and inference host. Encrypted at rest from the first boot.
Peak draw under combined CPU+GPU load lands around 600W, comfortably inside the 850W supply, with room for the GPU’s transient spikes and a quiet fan curve.
Built from bare components, encrypted, and running Linux as a daily driver and local inference host. No API round-trip, no data leaving the box.