The last page looks pretty bad. If you look at the others it's more of a mixed bag, but yeah.
I don't remember what benchmark I ran before deciding to run it on my laptop. Given my work at the time probably pgbench, but I couldn't say for sure. It was long enough ago I also might've been benchmarking against ext3, not 4.
i think i was running it on 6TB conventional HDD RAID1. also note that the read and write speeds might be quite asymetrical... in general also depends on workload type.
yeah. it's already so terribly slow that it's unlikely that taking snapshots can make it any slower :-D