@Jezry It depends on what you wanna do and how you use it.
If you want to use old 68k programs like Wordworth, Final Writer etc. you may not need all this horsepower.
But if you want to watch 720p videos you need a strong CPU and optimized player. If you want to play almost 4K video you need strong graphics cards with accelerated video playback. And the above can be done with live streams from the internet (YouTube, Twitch, Vimeo and many other) without any issues.
Also, if you want to use development IDEs like Codebench (
http://codebench.co.uk/) for your development needs, and a strong Web browser for your internet needs, a strong CPU is needed. Even the usage of fast SATA against old IDE is something that makes things much faster. If you want to render your Lightwave scenes fast and even use applications like Blender, strong CPUs come handy with that as well. And best of all, if you want to do all the above in parallel, while you listen your music.
And finally, if you want to play full HD (1080p) video games with great graphics, or emulate older consoles like SNES, NEO GEO, PS1 and MAME arcade games, you surely need strong cpus for that.
For some games have a look at:
http://hunoppc.amiga-projects.net/https://www.amigans.net/modules/news/article.php?storyid=2724https://www.amigans.net/modules/news/article.php?storyid=2778https://www.amigans.net/modules/news/article.php?storyid=2831Feel free to ask for more details if you want.