I play on my 6 yrs toshiba satellite laptop with sims 4 which high in ram. But staying it on too long, it is safe? Also it has 800mb free when reach about 85 percent.
How are you observing the Memory %? Task Manager, Resource Monitor, some third party utility?
Does the game (Sims 4) performance actually slow down or are there other problems?
Update your post to include full system hardware specs and OS.
What size drive is installed in the Toshiba laptop and how full is the drive?
Do you know if the laptop's drive has ever been "cleaned" via Disk Cleanup or CCleaner?
Or (only if a Hard drive) defragmented. (Does not apply to SSD).
No need to immediately do anything per se.
Just provide more information.