Question Higher End PC struggles with Multitasking and can't play a number of games

[Garzhvog]

Hey all!
I recently made a few upgrades to my old PC due to some RAM issues, and now despite the amount of money I've put into it, is running worse than it did before.
My computer struggles with basic multitasking, often having to close my browser while gaming as it ends up lagging out the game. (Not an internet connection issue)
It even struggles opening simple things such as windows explorer and task manager, and moving windows across screens often takes 5seconds minimum for it to realise what I'm asking it to do.
Specs are as follows:

• Intel i7-10700K CPU
• 64GB of RAM
• TUF B560M Plus Wifi Motherboard
• Kingston SNVS1000G SSD
• Nvidia GeForce RTX 3070
• 3x Predator XN3 Monitors

According to Task Manager, CPU idles around 30%, and shoots up to minimum 80% whenever I try to do something like open a new tab in Chrome / Firefox.
I've also ruled out overheating and dodgy hardware as I've swapped each piece out without the issue changing, so my guess is it's something software related.
I've spent ages talking with tech related friends and trawling the internet but I've not found any other solutions that aren't generic "my computer slow" problems.
Anyone please able to help me out?
Thank you.

Also as a side note, why does my computer lag freeze for a second every time the windows desktop background changes?? What's that about

 

[rgd1101]

fresh os install?
brand and model of the psu?
how full are the ssd?
latest motherboard bios?
check cpu/gpu temp?

 

[Eximo]

64 GB of memory on a consumer board is quite the feat, what speed is that running at?

Have you run any extensive anti-malware and anti-virus programs lately? Want to make sure your computer hasn't been hijacked with a crypto currency miner or a netbot.

When in doubt, scorched earth. Re-install the OS.

As for the background images, how many files are in the directory? That can have a huge impact on things if there is a large cache of images. Used to run into that all the time where people had EVERYTHING in the root photo album and used it as their screensaver. (And I actually once ran into the unicorn of multiple screen saver applications trying to launch at the same time. back when you could do that)