I would wait at least a few months
I am stuck at 3.7.1 with 4.9.27-ZS , 32 bits.
I tried 3.8 on a vbox dev env in order to compile apu drivers but dev env is still broken, I get segmentation fault error when I try to compile the kernel.
As for memory utilization.. never paid attention:
Memory 3629532 kB (5% used)