The reason I recommend more than what you're recommending is because most PC games now are just unoptimized ports of the console code. If you're running pure PC games, yes, you are absolutely correct. But when you load up a game with code that was developed for console first, you're going to see the problem.
I'm mainly playing Warthunder and Doom 2016. No exactly thirsty games as far as resources go.
In both cases, it's your video card though more on Doom than Warthunder (in fact, war thunder might be fine so I'll wager you get "okay" performance on war thunder).
https://www.systemrequirementslab.com/cyri/requirements/doom/13138
https://www.systemrequirementslab.com/cyri/requirements/war-thunder/11603
Doom requirements:
DEDICATED VIDEO RAM: 2048 MB
That's over and above what the OS is using. You technically hit minimum requirements but not functionally.
It looks like the video is a bottleneck for sure. I'd still say that if you can, replace that hard drive. 5400 is just plain slow and there's no excuse for manufacturers to make them that slow any more.
Yeah but I don't really think a 16-32gb card will really fit there when a 6-8 will do just fine