With SD you have a lot of control over not just basics like image size and prompt complexity, but also things like how many iterations of which different sample

With SD you have a lot of control over not just basics like image size and prompt complexity, but also things like how many iterations of which different sampler(s) get used. So speed can vary wildly depending on how you're choosing to use it. And that's without even getting into the wide variance of hardware. But generally speaking, it will usually be significantly faster than one image per minute.