I ran two powertop reports comparing 4.14.33 and 4.16.1.

The most obvious difference is this on 4.16.1:

--8<---------------cut here---------------start------------->8---
 *  *  *   Top 10 Power Consumers   *  *  *

Usage;Events/s;Category;Description
100.0%;;Device;Audio codec hwC0D0: Realtek
  0.0%; 47.0;Timer;tick_sched_timer
  0.2%; 38.0;Process;[PID 1258] xterm 
  0.0%; 34.3;Process;[PID 539] dzen2 -p -dock -ta l -fn DejaVu Sans Mono 
  0.7%; 21.3;Process;[PID 568] /gnu/store/07g1rwvrj7wn4sw6hx10hbvcs1v2adyf-emacs-prerelease-26.1-rc1/bin/emacs-26.1 --daemon -f exwm-enable 
  0.1%; 22.3;Interrupt;[0] HI_SOFTIRQ
  0.3%; 12.9;Process;[PID 538] conky 
  0.0%; 13.1;Process;[PID 8] [rcu_sched]
  0.0%;  8.6;Process;[PID 428] /gnu/store/183jf5g6qsql1i8zrgnziz5psvms68pc-xorg-server-1.19.6/bin/X -xkbdir /gnu/store/fpgz8f64dnz7szskjybrwkz4l9yl1
  0.0%;  6.0;Timer;intel_uncore_fw_release_timer
--8<---------------cut here---------------end--------------->8---

That Realtek audio codec looks awfully suspicious.

Sounds a like a think to report on the kernel mailing list?

-- 
Pierre Neidhardt