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Basic common sense would tell you that starting with an assumption and working backwards to justify that assumption is called succumbing to confirmation bias.
by bloppe 4y ago
Basic common sense would tell you that starting with an assumption and working backwards to justify that assumption is called succumbing to confirmation bias.
I sourced my cost/flop estimate from here: https://aiimpacts.org/2019-recent-trends-in-gpu-price-per-flops/ https://aiimpacts.org/2019-recent-trends-in-gpu-price-per-fl...
I'll acknowledge that a fleet entirely made up of A100 GPUs running at full capacity 100% of the time with Azure's 3-year commitment pricing (likely very low margin) would make this 5 orders of magnitude cheaper. But the sequential nature of transformers makes it difficult to achieve perfect utilization, and there aren't enough A100 GPUs in the Azure fleet to serve ChatGPT's billion users, so they're certainly running on mostly lesser hardware. Also, my estimate was for GPT-3 not 4, and neglected to address any memory or bandwidth costs, not to mention the costs to train and iterate on the models in the first place, including legions of data curators and many researchers commanding million dollar salaries.
If ChatGPT plus is $20/mo and each user uses it ~10 times per day, then MS/OpenAI would break even if my estimate were 2 orders of magnitude too high. Within the year, we'll have a much better idea of the real cost of these models.
- zamnos 4y agoYou can be sure Open AI isn't even paying Azure's punlishedy 3-year commitment pricing rate. The other thing to note is that OpenAI limits paying users to X queries per Y hours in GPT-4, something like 3 per 5. Which means the GPT-4 fleet is quite limited.
- int_19h 4y agoGPT-4 cap is currently at 25 messages every 3 hours. It also keeps saying "expect significantly lower caps, as we adjust for demand", but it's been three weeks now and they haven't lowered it yet.
- jsnell 4y agoUhh... I'm pretty sure that page is about the price of buying an entire GPU that does N GFLOP/S in perpetuity. It has no relevance to the calculation you did, unless you assume the GPU is used for one second and then thrown in the bin. > I'll acknowledge that a fleet entirely made up of A100 GPUs running at full capacity 100% of the time with Azure's 3-year commitment pricing (likely very low margin) would make this 5 orders of magnitude cheaper. But the sequential nature of transformers makes it difficult to achieve perfect utilization, I don't think you've thought this through. There's no realistic level of utilization that's going to make up for 5 orders of magnitude. An unimaginably crappy 1% utilization would still leave you off by 3 orders of magnitude. This very submission about OpenAI having to suspend selling subscriptions makes it pretty clear they're not having trouble with low utilization... > If ChatGPT plus is $20/mo and each user uses it ~10 times per day, then MS/OpenAI would break even if my estimate were 2 orders of magnitude too high. You do understand that this doesn't actually support your initial estimate, right? It just makes it more obvious how ridiculous it was.
- ericpauley 4y agoYup. GP is conflating FLOP/s and FLOPs.