Question Dell XPS 9560 performance issues

Jan 17, 2021
i bought this laptop second hand. 1080p model with i5 7300hq and gtx 1050, 8 gb ram, 512 ssd (99%, SP a55)
previous owner told me he had underclocked cpu for better battery

here are the issues i face:
windows explorer.exe slowly keeps taking more ram until it tops at 4000mb as shown by task manager, then i restart it. it is really weird, cpu usage is usually under 1 percent.
I often see "antimalware service executable" and "system interrupts" in task manager

download fh4 and it gave me low streaming bandwith error

when i play pes 21 the game occasionally stutters

downloaded project cars 1, as shown in the picture fps sits at 25-33, on low graphics settings 1080p. From what i have seen on youtube it should be giving me at least stable 60 fps on that.

I think the issue is hardware related, checked ssd but it is working fine.

Also, when the laptop is newly turned on windows explorer doesn't work, it says 'working on it' for at least 8 minutes. Then it starts working normally.

everyday browsing and office work is fine though.

thanks in advance