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by imiric 852 days ago
> On vast.ai renting a 3x3090 rig is $0.6/hour. The electricity price of operating this in e.g. Germany is somewhere about $0.05/hour.

Are you factoring in the varying power usage in that electricity price?

The electricity cost of operating locally will vary depending on the actual system usage. When idle, it should be much cheaper. Whereas in cloud hosts you pay the same price whether the system is in use or not.

Plus with cloud hosts reliability is not guaranteed. Especially with vast.ai, where you're renting other people's home infrastructure. You might get good bandwidth and availability on one host, but when that host disappears, you should hope that you did a backup, which vast.ai charges for separately, and if so, you need to spend time restoring the backup to another, hopefully equally reliable host, which can take hours depending on the amount of data and bandwidth.

I recently built an AI rig and went with 2x3090s, and am very happy with the setup. I evaluated vast.ai beforehand, and my local experience is much better, while my electricity bill is not much higher (also in EU).

4 comments

Well rented cloud instances shouldn't idle in the first place.
Sure, but unless you're using them for training, the power usage for inference will vary a lot. And it's cumbersome to shutdown the instance while you're working on something else, and have to start it back up when you need to use it again. During that time, the vast.ai host could disappear.
Most people don't think of storage costs and network bandwidth. I have about 2tb of local models. What's the cost of storing this in the cloud? If I decide not to store them in the cloud, I have to transfer them in anytime I want to run experiments. Build your own rig so you can run experiments daily. This is a budget rig and you can even build cheaper.
Let me add that moving data in and out of vast.ai is extremely painful. I might be overprivileged with a 1000 MBit line but these vast.ai instances have highly variable bandwidth in my experience; plus even when advertising good speeds I'm sometimes doing transfers in the 10-100 KiB/s range.
Data as well. I have a 100TB NAS I can use for data storage and it was honesty pretty cheap overall.
Well if you are not using a rented machine during a period of time, you should release it.

Agreed on reliability and data transfer, that's a good point.

Out of curiosity, what do you use a 2x3090 rig for? Bulk not time-sensitive inference on down quanted models?

> Well if you are not using a rented machine during a period of time, you should release it.

If you're using them for inference, your usage pattern is unpredictable. I could spend hours between having to use it, or minutes. If you shut it down and release it, the host might be gone the next time you want to use it.

> what do you use a 2x3090 rig for? Bulk not time-sensitive inference on down quanted models?

Yeah. I can run 7B models unquantized, ~13-33B at q8, and ~70B at q4, at fairly acceptable speeds (>10tk/s).

if you are just using it for inference, i think an appropriate comparison would just be like a together.ai endpoint or something - which allows you to scale up pretty immediately and likely is more economical as well.
Perhaps, but self-hosting is non-negotiable for me. It's much more flexible, gives me control of my data and privacy, and allows me to experiment and learn about how these systems work. Plus, like others mentioned, I can always use the GPUs for other purposes.
to each their own. if you are having really high-sensitive conversations with your GAI that someone would bother snooping in your docker container, figuring out how you are doing inference, and then capturing it real-time - you have a different risk tolerance than me.

i do think that cloud GPUs can cover most of this experimentation/learning need.

together.ai is really good but there is a price mismatch for small models (a 1BN model is not x10 cheaper than 10BN models)

This is obviously because their are forced to use high memory cards.

Are there ideal cards for low memory (1-2BN) models? So higher flops/$ on crippled memory

> built an AI rig and went with 2x3090s,

Is there a goto card for low memory (1-2BN) models?

Something with much better flops/$ but purposely crippled with low memory.

with runpod/vast, you can request a set amount of time - generally if I request from Western EU or North America the availability is fine on the week-to-month timescale.

fwiw I find runpod's vast clone significantly better than vast and there isn't really a price premium.