High RAM usage on i3wm

Like the title says, I’m seeing fairly high RAM usage on i3 - idle around 700-900mb on a fresh reboot with nothing open. Sometimes it will creep up to 3 or 4gb with only Firefox open and 5 or 6 tabs. I also have GNOME and Cinnamon installed and am using GDM (although I’ve tried LightDM and it didn’t seem to make any difference), so I suspect there are some GNOME services running in the background that aren’t needed on i3. What’s the best way to track down what processes can be safely killed, and is there a way to only have those autostart when I log into a full desktop?

I’m not sure 700M would be considered high. Have you compared it to not having X running at all? On TW on an old Core2Duo right after booting, I get:

# free
               total        used        free      shared  buff/cache   available
Mem:         8139392      432296     7738928        2088      210252     7707096
Swap:        1534172           0     1534172

I guess I mean high in comparison to what one would expect while running a window manager instead of something like Gnome. On this same PC when I log into Gnome, the RAM usage is very similar. On an old Core 2 Duo Thinkpad (T500) I have Arch installed with i3 and see 200-300 idle on boot. I realize Arch and TW may be setup a bit differently though.

At the end of the day it’s not a big deal, I have 16gb and never get close to maxing that out, I was just curious since it seems higher than what I’d expect.

The more RAM is installed, the more use of RAM the kernel and various apps take advantage of. Here with 32G RAM it’s pretty typical after a few days’ uptime that more than twice as much RAM is devoted to cache than is to the apps I have sprawled across 8 virtual desktops.