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Precacher -Load before you lag-

I recommend switching to the 64-bit branch for a potential cache above 4GB.
In case of multiplayer: This can cause client time out when the host does this. Adjust to cl_timeout 500 or more and let the clients start the caching process before the host starts it.

Loading resources from the hard drive into the CPU takes much time and causes the game to temporarily freeze (aka lag.) To fix this, games will utilize the RAM to cache elements near the CPU for quicker access times, usually before they're actually required (hence loading screens.) Gmod only loads the minimum amount of assets (e.g. the map) on startup, which is why you'll often lag the first time a model or sound is used, but not the subsequent times.

The context menu now comes with a new app called "Precacher". In here, you can select your favorite addons (or base HL2 NPCs) and load their models and/or sounds. This will freeze the game until it's complete without a fancy loading screen, but it will play a sound and close the menu upon completion. Once done, you should have significantly lower inital lag for any assets you cached, like guns or NPCs.

The Gmod cache is not unloaded upon singleplayer map change, so you won't have to re-cache the assets. However, if you restart the game, much of it will be lost, and once you shut down your PC, the entire cache is gone. That's why Gmod's second start is usually faster than the first one, since the old RAM hasn't been fully overwritten yet. Gmod may also un-cache certain assets over time on its own, so use the 64-bit branch to maximize the cache usage.

If you are tech-savvy then you can also toy around with the precache commands, which are precache_sound_dir and precache_model_dir. The amount of information printed to the console is controlled by precacher_verbosity. Use precacher_verbosity -1 to make it shut up, and precacher_verbosity 2 to be informed of every single action.
Finally, there are also the commands precache_all_addons (not recommended if you have many addons enabled) and precache_all_hl2, which you can add to the Server side of my Auto Command on Start addon.


Have fun!!!