Would help a little if you provided the make, model, and serial number of the laptops

(the serial number only will help show what was in the configuration of the machines originally and the age, no personal info is shown)
Just because a CPU is newer does not necessarily mean it's automatically better. To confirm you have these 3?
1: Intel Core i5-4310M @ 2.70GHz
2: Intel Core i5-7300U @ 2.60GHz
3: Intel Core i7-4940MX @ 3.10GHz
According to
CPU Benchmark, the 4940MX should be running more efficiently. Considering that has 16GB too (unknown specs), that machine should be better at handling processes. One of the first things to check is to see what is running at the time of the install, to make sure nothing else is taking up resources while running the setup. (Task Manager)
You didn't mention if they are all Windows 10, Windows 11, or mixture, or if they are updated... Also check for virus/malware.
You didn't mention if they all have similar software installed, or if they are different, i.e. Computer 1 is barely used and only for web surfing while Computer 2 is used for gaming while Computer 3 is used for Video Editing...