I'm beginning to suspect that you've installed the 64-bit version of Slimjet (which uses massive amounts of memory and is still a bit buggy), rather than the 32-bit version (which is generally recommended, even for 64-bit systems, uses less memory and is totally stable).
You should be able to check which version of Slimjet you've got via
Cogwheel > Settings > Help Centre > About Slimjet
although, obviously (if you've got a different version to me), you might see a slightly different path.
I'm seeing this when I do that:
"Version 28.0.3.0 (based on Chromium 85.0.4183.69) (Official Build) (32-bit)"
If you've got the 64-bit version, I suggest uninstalling it, RESTARTING YOUR COMPUTER and then installing the 32-bit version from here:
https://www.slimjet.com/en/dlpage.php
If you've already got the 32-bit version, but it's not showing as "Version 28.0.3.0", try updating it. (Cogwheel > Settings > Help Centre > Check Update).