Let me give diagnosis:
The one with Core i5 is 4th gen., and one with Core i3 is 6th gen.
Irrespective of generations (but then difference must not be huge, like comparing 1st gen. with current 10th gen.) i5 would be better than i3. I think, processors are not an issue.
Main issue seems to be ineffective RAM usage, due to 32 bit OS in Core i5 computer.
If you could see, i3-6006U is using full 4 GB RAM, however, i5-4200U is able to only use 2.41 GB RAM out of 4 GB RAM available, due to 32 bit Windows OS.
You are using 32 bit Windows OS on a 64 bit processor. How will it be able to perform?