It shouldn't be power-hungry... A lot of OpenBSD developers use OpenBSD on their ThinkPads. It should work fine. Maybe you haven't configured power management.
You're telling me what it shouldn't be or should be, but I am telling you what it is.
You are free to search marc.info for the fruitless threads of me trying to solve multi-second system freezes when opening emacs or changing workspaces if you like.
The fact that the devs dogfood their stuff is irrelevant: it doesn't perform even remotely as well as Linux on the same (modern) hardware.
In OpenBSD you can let the kernel do the power management with "sysctl hw.perfpolicy=auto".
Also there was fix in ACPI in 5.8 to fix power use in newer processors. If I remember it correctly the processor didn't use the deep sleep states so they consumed more power.
You are free to search marc.info for the fruitless threads of me trying to solve multi-second system freezes when opening emacs or changing workspaces if you like.
The fact that the devs dogfood their stuff is irrelevant: it doesn't perform even remotely as well as Linux on the same (modern) hardware.