Yes. Please realise that things that can be evicted from RAM include the code and static data for the programs you are running. If you switch off swap, then yo

Yes. Please realise that things that can be evicted from RAM include the code and static data for the programs you are running. If you switch off swap, then you are disqualifying stuff like data pages that a program will set up on process start and then never touch again, which is sometimes a distressingly large amount. That then uses up RAM that could be used to provide a more responsive system. The ideal contents of swap are those data pages that are never going to be touched again. On a normally running system that doesn't have massive memory pressure, that is basically all that will make it into swap, and that's fine because those genuinely are pages that you won't need, and they aren't causing the problems with alt-tab. What probably is causing the problems with alt-tab are one of two possibilities. Either the system is over-burdened and it is having to swap out large amounts of working set (to which the solution is to install more RAM or reduce the load, not switch off swap), or you have been transferring large amounts of data through RAM, causing the disc cache system to evict parts of a program you haven't used for a long time in favour of these files that another program keeps loading in (and switching off swap won't help much with that either, because the system is being quite happy to evict parts of that program that aren't anonymous pages - a solution is to get the program that is handling lots of data to ask the OS kindly not to cache certain things, if it for instance knows that it will only load them once). I do think that Linux's behaviour has improved massively over the last 10 years or so. A lot of these myths about swap were created before the improvements, and we should stop believing them.