Hello I am new here and I simply came here to try and find a solution to this problem and ended up doing it myself..
To start off with no older processors are not better! Technology only gets better and better with time! It's a fact, agreed upon by everyone otherwise experts would be exploiting this for business!
Now to fix the problem which was frikin' irritating me (and I'm sure a lot of other players with "up to date processors").
NOTE: This simply worked for me, I'd crash whenever there was a lot of stuff going on (usually around 1500MB of memory).. It is frustrating I know, I hope this works for you as it has for me (for the record I have an intel core i7-4790k CPU @ 4.00ghz). But after doing what I'm about to show you (easily) it should solve the problem!
1) Launch Edain as you would
2)alt+Tab and open your Task Manager
3)Go to details and find game.dat with the RotWK icon obviously
4)Right click it and go to "set affinity"
5)Disable all and enable just one (I went for CPU 01)
It should work now without crashing.. I played 4v4 on epic battle on Ultra settings all AI set to brutal..
You may have to do this every time you start the game or I'm sure you can modify the shortcut so it prompts it to do simply by adding "c:\windows\system32\cmd.exe /C start /affinity x" in the front in the target in the shortcut's properties but I'm literally too lazy to try that out (but it would be logical for it to work).
I'd finally like to say amazing mod from the Edain team! Definitely made RotWK one of my most favourite games to play (and I can play pretty much anything on my PC)! Mordor is by far my most favourite faction to play as with the whole Sauron setup! I hope to see this mod carry on for many more years to come!
I hope my fix works for others as it did for me! Thank you and cheers guys