Has anyone had luck buying used GPUs, or is that something I should avoid?
And old mining GPUs are A-OK, generally: Despite warnings from the peanut gallery for over over a decade that mining ruins video cards, this has never really been the case. Profitable miners have always tended to treat these things very carefully, undervolt (and often, underclock) them, and pay attention to them so they could be run as cool and inexpensively as possible. Killing cards is bad for profits, so they aimed towards keeping them alive.
GPUs that were used for gaming are also OK, usually. They'll have fewer hours of hard[er] work on them, but will have more thermal cycles as gaming tends to be much more intermittent than continuous mining is.
The usual caveats apply as when buying anything else (used, "new", or whatever) from randos on teh Interwebz. (And fans eventually die, and so do thermal interfaces (pads and thermal compound), but those are all easily replaceable by anyone with a small toolkit and half a brain worth of wit.)
Still waiting on being able to afford the next 4090 + egpu case et al. There are a lot of things this rig struggles with running OOM, even on inference with some of the more recent SD models.
If you use a mouse with more than right-click and scroll wheel, with side buttons for example, then you’ll need extra software.
Grok-1 was running on a M2 Ultra with 196GB of ram.
Imo the 4070 super is the best value and consumes the least amount of Watts, 220 in all the top 10.
So anything with one and some ECC RAM aka AMD should be fine. Intel non-xeons need the expensive w680 boards and very specific RAM per board.
ECC because you wrote server. We're professionals here after all, right?
FWIW, I was in the same boat as you and decided to start cheap, old game machines can handle AI shenanigans just fine wirh the right GPU. I use a 2017 workstation (Zen1) and an Nvidia P40 from around the same time, which can be had for <$200 on ebay/Amazon. The P40 has 24GB VRAM, which is more than enough for a good chunk of quantized LLMs or diffusion models, and is in the same perf ballpark as the free Colab tensor hardware.
If you're just dipping your toes without committing, I'd recommend that route. The P40 is a data center card and expects higher airflow than desktop GPUs, so you probably have to buy a "blow kit" or 3D-print a fan shroud and ensure they fit inside your case. This will be another $30-$50. The bigger the fan, the quieter it can run. If you already have a high-end gamer PC/workstation from 2016, you can dive into local AI for $250 all-in.
Edit: didn't realize how cheap P40s now are! I bought mine a while back.
Yeah, I could rent time on a server, but that's not as cool as just having a box in my house that I could use to play with local models. Feels like I'm missing a wave of fun stuff to experiment with, but hardware is expensive!