My HP 250 G6 laptop gets an average of 18th percentile from 3 different sites.
I recently added 8Gb RAM and a 1Tb SSD and reinstalled windows. Since then a few programs for my hobby of Astrophotography have been added. It is sluggish in that it takes 5-20 secdonds to resond to an instruction. I have checked with HP who confirm the RAM is correct for the laptop.
You also need to compare your benmark results against the same machine model or is that what you did to get the 18%? There are sometimes options for different CPUs (which would make a significant difference) or graphics processors. I would also suggest you run the HP diagnostic test. When you reinstalled Windows, did you do a "clean" (complete) reinstall? I agree with the prior response that adding more RAM won't always help. You need to use the task manager and see how much "paging" is being done. If you are doing photo processing, that can take a lot of CPU/Graphics horsepower.
Correction. I apparently haven't looked at memory paging in task manager for a while. Used to be there but I can't find it now. It is still in Resource Monitor. Just type that in the search bar and open it in admin mode. Click on Memory tab and click at the top of the Hard Faults column once or twice to sort on that column. That will display page faults/second for each running process with the worst one listed first. If you are seeing large numbers of faults (many thousands/second) that may indicate a slowdown as much page swapping to the SSD is going on. Usually, more RAM is the solution, but not always.......