/SLASHPLAY
How to turn on slow motion in GMod
With sv_cheats 1 on, type host_timescale 0.5 in the server console to run the whole game at half speed; host_timescale 1 is normal.
host_timescale
Speeds up or slows down the whole game, players and physics included; needs sv_cheats 1.
host_timescale <scale> Examples
host_timescale 0.5 Half speed.
host_timescale 1 Back to normal.
Arguments
scaleRequired- Game speed multiplier, 1 is normal.
On SLASHPLAY
On SLASHPLAY the console accepts values from 0.05 to 10; outside that the server would stop answering or stall.
What it does
Values below 1 give slow motion for everything, values above 1 fast forward. For slow motion physics only, use phys_timescale, which needs no cheats.
The game's own description: Prescale the clock by this amount.
Run it on your server
On a SLASHPLAY server, type it in the Console tab of the server page; the reply shows right under it. A value set there lasts until the server restarts. To keep it, add the line to garrysmod/cfg/server.cfg. New to this? Start a GMod server first.
Your own
GMod server.
From $0.03 an hour, only while it runs. New accounts get 6 free tokens.