This may just be me, but my computer is painfully slow in many circumstances. While fast graphics does reduce the glitch rate, half the time it still screws up and ends up not working for most of the song. A no graphics mode that displays no notes would probably help with the glitching in non-editing mode.
Probably just ensure you have as much resources as possible on your browser and close / end any other programs you have open. Task manager can help with that, if you have access to it.
Yes there are many ways to speed up your computer. NONE of which involve downliading "optimizer apps" by the way.
The first thing you should do is turn off applications running at startup. A lot of apps try to run as soon as you boot the computer, like Steam is one of them, which can slow it down.
You may also consider removing your antivirus, then using the default one (the default one is actually pretty good). Antiviruses are resource hogs and a lot of them steal your personal information in the background, like Avast and AVG.
Try clearing browser cache and cookies. This will log you out of websites but probably improve the performance of your computer.
Try turning off windows telemetry because all it does is steal your personal information and slow down the computer.
If none of that works well enough, you COULD try a windows10 debloater script. Be warned though, that these will remove a lot of things on the computer, like cortana, livetiles, windows store, etc. It may help improve the performance a lot but it will also remove a bunch of default stuff.
I recommend opening Task Manager to see which parts of your computer are having the most trouble, go to performance tab on the task manager, then do what you can to get the performance to be better
