I have the following kernels installed:
- linux-zen (Zen)
- linux-rt (RealTime)
- linux-hardened (Security Hardened)
- linux-lts (Long Term Support)
- linux-tr-lts (Realtime LTS)
When I boot up, I try the different kernels from time to time just to see if anything interesting happens. It never does.
My question: How do I actually physically notice the difference between these kernels? If I use RT, does Firefox spawn quicker (in my testing, no, not really)?
What are some use cases when I can really see the difference in these kernels?
Zen and “mainline” (default/vanilla) are generally fine for “desktop use” and gaming. Zen is basically the mainline kernel with some tweaks. They are mostly concerned with latency, reducing the maximum time a process can spend blocking the processor - among other things.
This can lead to less input lag or a “smoother” desktop experience, but overall performance is as good as mainline at most. Slightly worse in some scenarios.
Hardned is a tradeoff afaik. You will stay behind mainline a bit, but get extra hardening. This can also impact performance, but rarely does in a meaningful way. If you don’t have any specific reason to use it, e.g. you carry it around on a laptop with sensitive data, I would look at other ways to harden my system first (firewall, encryption, access control, anti-virus, sandboxing, VPN…).
Pretty much the same goes for LTS, but with the focus more on stability than security.
RT is only for special applications.