Hey there,
It sounds like what you’re experiencing may be a problem with the browser’s hardware acceleration.
I recommend checking here How to fix/turn on your browser's hardware acceleration and ensuring that your browser is configured to make use of it.
If that doesn’t resolve it, check your OS settings and set your browser e.g. Chrome or Firefox to run at high performance mode. Often, a machine might have a battery saver or office mode or some other setting that will prevent it from using the GPU, so make sure such settings aren’t turned on, if your machine has any.
As long as you meet the Minimum Requirements | Foundry Virtual Tabletop you shouldn’t need to upgrade hardware, but hardware acceleration is necessary.
Another thing to check is whether your poor performance persists with modules disabled. Modules run in the browser and can negatively impact performance. If poor performance consistently results from loading a specific module, it might help to exclude that module or to reach out to the module developer for help in troubleshooting it.
Another thing that’s worth checking is your world size, since large world sizes can contribute significantly to browser load (which can manifest as ‘lag’) and slow world loading times when loading over a network.
Hope that helps!