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It’s a combination of things, accounts come in usage Tiers based on how much you’ve spent and how much time since your first spend, so the lower tiers can have a larger latency, also a great deal of extra load is on the system as people test the new features out, this will settle with time, usually takes about a month to calm down, at least it did last time GPT-4 was released, might take a bit longer with all the new stuff this time.