If it were me (and I’m no expert), I’d open a program that provides some details about your system such as
htop before you use the program(s) that you suspect create issues for your system.
You should get a feel for what normal behavior looks like with the program first, so it’s easier to spot issues when they occur. To get some feel about what
htop can do, have a look at what our manual says about it, ie. https://manual.lubuntu.me/stable/3/3.1/3.1.2/htop.html . The manual focuses on using it, which is a huge start, but how your machine operates really requires you to on occasion watch it as you do your normal tasks.
When you start the program that creates an issue, have the
htop window already visible and look for what resources is it using; are its needs excessive? (comparative to your available resources). You haven’t provided details of how much RAM you have, but some web pages can use tremendous amounts of RAM, so if you’ve a limited amount - you may need swap (I sure do on my boxes for how I use my systems).
There are pros and cons to swap, and whether or not you need it. It can add greater costs for you (eg. you’re using SSDs and not HDDs; longevity cost) in providing increased speed, but can also cause overhead slowing your system down. Ubuntu can use a swap partition or swap files. If I’m dual booting (two GNU/Linux systems share the box) I use a swap partition so they can share the space, but where a device has only a single OS I usually opt for swap files.
Your issue could be something else, waiting for network storage is another example of what can cause temporary delays for me (much of my storage is network based, or NFS). Monitoring tools like
htop can help me detect those issues, though I’d likely use other tools in my arsenal if I thought it was that.
I’m largely using
htop because it’s pre-installed with Lubuntu 20.04 LTS, plus it’s light (some tools are heavy & you cannot afford to use them when resources are strained with issues like you’re describing), so
htop is a great first peek when you start looking for causes to performance issues.