Anything less than an RPI3b+ and you’re wasting your time with processor and memory intensive tasks. The older boards are fine for basic duties but certainly not for the likes of a fully kitted out HG install and definitely not with any further server applications installed on top of that.
Why not recommend rpi4? 2g ram basic model is same price as rpi3. Along with an old antique 16gb SSD, it is as fast as any of my other fancy computers. HG runs well on it. I haven’t measured boot time but I think it is around 10 sec. I generally use TeamViewer to work with it.
If you noted my opening remark…Anything less than an RPI3b+ and you’re wasting your time with processor and memory intensive tasks.That would intimate the inclusion of an RPI4 too.
There are other issues to consider in relation to GPIO operation and a number of other architectural differences between the RPI3b+ and the RPI4. You can see an example of these nuances on the current issues reported on the author’s GitHub.
As far as I’m aware there’s been no development work done with HG and the RPI4 so personally I wouldn’t recommend that platform until the author has verified that he has tested the core code on it. Of course it’s up to each individual use what platform they decide to run HG on.