x5 needed RAM because it was 5 times faster.
Elaborate on this please. How does it need more memory for more speed?
Only thing I can think of is more players, but that is not "because it was 5 times faster".
In itself it is an issue coming from none optimized code or some suboptimal decisions in the development process.
A browsergame like travian should not use gigabytes or ram or have heavy lagging issues when opening the map, even with loads of players.