linuxmemes

"i paid for the whole RAM imma use the whole RAM"

–me in 2010 using console commands to turn off all the particle effects in Portal so that I could boost my fps to ~20 w/ minimum settings (the laptop did not have a graphics card lmao)

This applies when RAM is used as temporary cache or something that can be instantly freed the moment it is needed otherwise. This doesn't really work for justifying higher RAM use by KDE, unless you would never need that RAM for anything else anyway.

I use KDE because it is good, though. Also I don't think KDE even uses more RAM than other DEs that are designed to be lightweight. Last time I compared, it used the same or less memory as LXDE.

It's just really oversimplifying memory usage. OS designers had that same thought decades ago already, so they introduced disk caching. If data gets loaded from disk, then it won't be erased from memory as soon as it isn't needed anymore. It's only erased, if something else requests memory and this happens to be the piece of "free" memory that the kernel thinks is the most expendable.

For example, this is what the situation on my system looks like:

free -h
               total        used        free      shared  buff/cache   available
Mem:            25Gi       9,8Gi       6,0Gi       586Mi       9,3Gi        15Gi

Out of my 32 GiB physical RAM, 25 GiB happens to be usable by my applications, of which:

• 9.8 GiB is actually reserved (used),
• 9.2 GiB is currently in use for disk caching and buffers (buff/cache), and
• only 6.1 GiB is actually unused (free).

If you run cat /proc/meminfo, you can get an even more fine-grained listing.

I'm sure, I could get the number for actually unused memory even lower, if I had started more applications since booting my laptop. Or as the Wikipedia article I linked above puts it:

Usually, all physical memory not directly allocated to applications is used by the operating system for the page[/disk] cache.

So, if you launch a memory-heavy application, it will generally cause memory used for disk caching to be cleared, which will slow the rest of your system down somewhat.

Having said all that, I am on KDE myself. I do not believe, it's worth optimizing for the speed of the system, if you're sacrificing features that would speed up your usage of it. Hell, it ultimately comes down to how happy you are with your computer, so if it makes you happy, then even gaudy eye-candy can be the right investment.
I just do not like these "unused RAM is wasted RAM" calls, because it is absolutely possible to implement few features while using lots of memory, and that does slow your system down unnecessarily.

I got plenty of ram. We’re using it.

I read this same principle in an arch or gentoo forum/manual. I can't even think of an argument against it tho? Unused anything is wasted by definition isn't it? I know I'm missing something obvious somehow