I have a recent x86_64 snapshot running on a ThinkPad, and it locks up every once in a while. I just noticed that it’s just the graphic interface, and I can still access via ssh from another host. “ps” shows everything is still there, but the thing that was running in a Terminal window has stopped doing its job - as of, apparently, the moment I touched the keyboard, so maybe it happens when there’s UI device input after it has been idle for a time.
On UNIX, I’d be getting more details out of ps - if anything is drawing a lot of CPU, RAM, anything stuck in “device wait” status. Does Haiku have any of that?