Using Google Earth, is using a 8 Gb instead of a 4 Gb (memory) would make a real difference. As well, 3.0 GHz instead of 2.8?

First, if your machine is infected with Malware, all bets are off. The malware could be doing literally anything in the background and using all your computer resources. It could also be recording all your user names and passwords and sending them off to some hacker in Russia. So you have to address that issue first.

Secondly, amount fo Ram. Maps should run fine on a modern computer with 4gb of ram. 8 gb will give a small improvement to overall system speed, especially if you have multiple programs open

Clock speed? That's not a good measure of CPU power, I have some old Vista vintage machines here with 3 gz clock speed that are pretty much dogs by today's standard. A modern 2.6 machine could have 10X the power because they have more and better CPU cores in the chip. So even with a lower clock speed they get more work done.

So between the malware and and old CPU, that's why your PC struggles. A Clean and more modern computer will run it fine, at 2.8 clock speed and only 4 gb of ram.

ram may make a difference if you are using all you have, taking the same cpu from 2.8 ghz to 3 will have very little impact

Yes