Because we use an efficient tab-UI, and grouping tabs into threads makes it easy to collect them, and we do that on different workspaces that reflect the different areas we work on. Where do you put all those dozens of tabs you opened in the last hour if you know you’re going to need them again later? Do you close all of them and start anew googling?
It’s fine, with tab-unloading you can have hundreds of tabs without much resource impact.
I guess so … Not something I do. I guess having an extension for vertical tabs or something like saved favorites would be okay. Having a bunch of open tabs doesn’t make any sense to me. 
The main problem is there are extensions/means for saving open tabs (export the URLs into files, save them as bookmarks, …), but I haven’t found one that also easily restores the complete state.
So if you work on a project and over time start to organize your open tabs into groups/subfolders they become like a file structure of “documents” I’m working with.
I wont delete all the “documents” I found over the last hours and their organization just because I have to put this particular project away for a while.
I don’t use 70 tabs, rather 15-20 max, but Tree Style Tabs do the job coupled with Auto Tab Discard.
You do have your answer though, vivaldi accounts for almost half of your used RAM. You do have enough RAM for your use case though, so there’s no mystery here.
???
Did you not read the issue? The RAM usage persisted after I closed vivaldi, and gotop is listing the processes by memory. Main is a video game, not a browser. I’ll close this issue for now since it seems reseating my RAM fixed it, and I haven’t had issues since.
EDIT: It hasn’t been fixed yet, seems to crop up after running a game. I’ll try the zram from bluish and see how that helps.
Do you have Vivaldi set to keep running in the background when you close it?
I never use that option on my browsers so I’m not sure if it could cause that issue, but it’s the default setting on many browsers
and 70 tabs 
lol
Despite closing every desktop app and my system monitor listing less then 1G of RAM being used by apps, I have just under 9G being used, this gets worse over time. (about 1G is being used by vivaldi to make this post)
Sounds like it’s a software issue with the game not hardware.
I was trying to say: what you are seeing is totally normal. If your system has tons of free memory and doesn’t actually need that RAM freed up for another process, it will just leave it cached there. If you wind up needing to use pages that were cached there later, great–they are ready to go. If not, no harm done.
Look, you have almost 10 GB in your RAM cache:
That exactly correlates with what you are describing. You open a bunch of applications, they actively use a bunch of RAM, you close them, the information those applications stored in memory stays in the buffer in case you need it again, until something else asks for the RAM.
I may not be explaining this well. If you have a moment, read the article posted above and it will probably make a lot more sense:
I would also still advise creating a swap device, even if it seems like your issue was caused by a badly-seated RAM card. It will make the way your system uses memory more efficient, and depending on the apps you run it can make things more stable/less prone to crashing as well.
I don’t believe it would be caused by a badly seated ram issue in my opinion. A badly seated ram module would more than likely cause the system to have errors and crash as opposed to high ram usage. 
Edit: I do agree with having swap though especially when gaming.
I agree, it is possible reseating the RAM coincided with some relief from the issue by coincidence. This is what was suggested as having fixed it at one point though:
My mistake though, I didn’t notice they edited in later that the issue returned:
It looks like some swap is on the way though, hopefully that will take the curse off. 
Garbage collection in Linux is a bit lazy. I noticed too my RAM stays marked as used when i close memory intensive applications. Linux has this philosophy of making the most use of your whole RAM instead of trying to keep the usage to a minimum. Empty RAM doesn’t do anything good for the system. It just sits there unused.
My main issue with this is there being no way to free up this RAM. It becomes a problem when I try to run a memory intensive game or application and my system locks up because of it. It seems an occasional reboot seems like the best way to clear it.
It is free. If an application needs memory, the kernel just overwrites the buffer. If nothing needs the RAM it just leaves the buffer alone, because why not?
Did you read the article yet? It mentions a way to manually purge the buffer if you insist on doing that.
How do I stop Linux from doing this?
You can’t completely disable disk caching, (but you can tune Linux’s “swapiness”). The only reason anyone ever wants to disable disk caching is because they think it takes memory away from their applications, which it doesn’t! Disk cache makes applications load faster and run smoother, but it NEVER EVER takes memory away from them! Therefore, there’s absolutely no reason to disable it!
If, however, you find yourself needing to clear some RAM quickly for some reason, like benchmarking the cold-start of an uncached application, you can force linux to nondestructively drop caches using
echo 3 | sudo tee /proc/sys/vm/drop_caches.
Can you do a df -h --type tmpfs just to be sure there’s nothing going on there?
Filesystem Size Used Avail Use% Mounted on
tmpfs 16G 655M 15G 5% /dev/shm
tmpfs 6.3G 1.9M 6.3G 1% /run
tmpfs 3.2G 80K 3.2G 1% /run/user/1000
That is pretty much normal and your /tmp is on disk not in RAM. /dev/shm/ feels a little bit high, but doesn’t explain the numbers you see. Half a gig though, what’s in there?
So you boot, log-in, check free -h and you immediately sit at 9-17 GB used memory?
And this happens with the normal or LTS kernel too?
PS: Also memory evaluation is hard, and plasma’s “new” System Monitor is not the best tool for the job. But if you use it go over to the Processes tab and also activate Show: All Processes in the drop down at the top.
The 9Gb was after a hour of playing a game with proton, I don’t have the normal kernel currently installed. The processes tab looks similar, with the memory % not adding up to actual RAM usage.
Estimating memory is hard because of e.g. shared libraries, so don’t expect that to add up to the used value. But the Processes view with All Processes shows you a lot more than just the Applications view.
Maybe some proton process isn’t shutting down properly, wouldn’t be that uncommon. You have to take a look when you notice the situation.