The default kernel installed in most distributions of GNU/Linux is more optimized for server tasks than userspace application that demand realtime feedback from kernel instructions.
Especially when using 64 bit applications for Multimedia/3D work, including simple tasks such as playing streams of data from services like Spotify, YouTube etc, you can benefit greatly if you throw out the default kernel in favor of a kernel optimized for fast redraws in memory allocated to applications that demands functions such as streaming multimedia with pre-compiled static kernel libraries. realtime gives Insanely better performance even in simple tasks such as music playback, not to mention communication on the bus between soundcards and the instructions, decompiled through their respective partners.
If you work with 3D apps such as Maya, and compositing in applications like Nuke, try a side by side comparison after switching to a RT kernel…
You will be amazed.