Small proof that UltraKSM’s really worth applying its patch to your Linux kernel: – Yeah, that’s correct – in ~ 10 minutes RSS goes down to 970 MB instead of 1.849 GB.
I’m not sure about increased CPU usage (twice as well), but even if it’s related to memory “compaction” it’s an even trade, as to me.
P.S. I bet it’s something your Mac still can’t do, isn’t it? ;-P