Purge unused

Some time ago my computer all of a sudden could no longer purge large amounts of data from my large models as it could before. I have a fairly new system with a fast processor but that isn’t the issue as my laptop which is 12 years old and runs v2018 can still do the process even if it’s purging large amounts like 100mb or more. Anyone had the same problem and found a solution? I know I need to purge more often but if I accidently go just a bit too far then I miss my chance and have to put it on my laptop which takes time.