1. Quit workspaces you're not actively using
The single biggest driver of Slack's memory use is how many workspaces you're connected to. Each workspace runs its own background sync process. If you're signed into four workspaces but actively use two, the other two are consuming memory for no reason.
To sign out of a workspace: click the workspace name in the sidebar → Sign out of [workspace]. You can always sign back in later.
2. Disable hardware acceleration
This sounds counterintuitive, but turning off hardware acceleration often reduces Slack's memory footprint noticeably. The reason: Chromium spawns a dedicated GPU process when hardware acceleration is on. Disabling it eliminates that process.
Go to Preferences → Advanced → Hardware Acceleration → toggle it off → restart Slack. Works on Windows, macOS, and Linux.
3. Quit Slack completely when you step away
When you close the Slack window, it keeps running in the system tray by default — still consuming a substantial amount of RAM in the background. Change that:
Preferences → Advanced → enable "Quit app when all windows are closed" (or equivalent wording depending on your OS). Then when you close the window, Slack actually exits.
4. Use the browser for secondary workspaces
If you have one workspace you use heavily and others you check occasionally, run the secondary ones in a browser tab. app.slack.com gives you most of the Slack interface and shares the browser process you're already running, instead of adding another Electron instance to your system.
We break down the full tradeoffs in Slack desktop vs browser: which uses less memory?
5. Clear Slack's cache
Slack accumulates cached files over time — images, file previews, call recordings. This mainly affects disk space, but a bloated cache can also contribute to memory use. Clear it via Help → Troubleshooting → Clear Cache and Restart.
6. Mute or leave channels you don't read
Slack tracks activity in every channel you're a member of. The more channels, the more it monitors. Mute channels you rarely check (right-click → Mute Channel), and leave channels you've never looked at.
If none of this is enough
These steps reduce Slack RAM usage, but they treat symptoms rather than the root cause. Slack's memory footprint comes from its architecture — it ships a full browser engine with every install, and no setting changes that.
If Slack uses too much memory even after applying every fix above, a native client is the permanent solution. msga connects to the same Slack servers you already use, but runs as a real desktop application without a bundled browser. At idle: ~60 MB RAM, ~0% CPU.