If they have 32-bit Windows 10 Home version then the most the operating system can use is 3.5GB so adding more memory does nothing. With the Mac OS the extra RAM was usable as a RAM scratch disk. But then the Apple operating system is a modern one and so has more capabilities and performs better than the Windows versions which are based on 1995 NT 3.51.
By that logic, Mac is an ancient system because it is based on the Mach and BSD Kernels which were started in 1983 and 1977.
The difference is that Mac OS X was based on NEXT that was created using the concepts of UNIX but not simply copying over the code. With Windows the code was taken as is from NT3.51 which in turn was hobbled in order to get around the key patents of IBM for OS/2. OS/2 had a communications module that protected the kernel while allowing multitasking.
Microsoft made a conscious decision to allow devices to directly access the kernel and that is what led to the Blue Screen of Death. I can plug a card reader or thumb drive into a USB port on a Windows computer and prevent it from booting or cause the BSOD to appear.
Microsoft created an architecture with multiple DLL's that can be at different version levels and reside in different directories and get called in a nearly random fashion depending on where the last installed application was coded to put a new DLL. There are the problems inherent to the Registry that provides a central location on every Windows computer and makes it incredibly easy to hack the machine and leave behind Trojans inside it to be activated on the next boot of the computer.
And then we have Framework that created its own problems and it is no fully supported but application developers are still using it. Add in the Visual Basic IDE with its bloatware and the macros that also greatly helped hackers.
With our Windows computers there are nearly daily patches and patches to patches but with the Mac OS the updates come once every 6-12 months. 99.9 percent of the time I spend fixing computer problems are with the Windows machines. 100% of the time and money spent on registry cleaners, spyware detection, anti-virus checks, and firewall maintenance is for the Windows computers.
I have worked with the operating systems sold by Microsoft since DOS 1.0 and every version of Windows and the Apple operating systems going back to 1977. The difference between the two companies is that Apple will produce a greatly improved operating system even if it means users will need to buy a new Apple computer to run it.
Microsoft wants to protect its Office monopoly and its near Wintel monopoly by making each new version of Windows able to run (although very slowly) on older computers and with older applications code. So it add UI layers and security layers on top of a poorly designed OS architecture.
I often see some aspect of Mac OS X that reminds me of mainframe operating system architecture and how control is decentralized for security and the use of priviledges to keep a novice from being vulnerable. I only see that with Microsoft with their Exchange server applications. Small wonder that for years Microsoft used Linux on its corporate email servers.