If you are unwilling to edit .lua files, you can fix the lag within your current campaign. This requires military intervention.
Open the DarthMod launcher. Go to Options -> Graphics -> Select the preset. empire total war darthmod ottoman turn lag fix best
Search for on ModDB or TWC. A user named 'JaM' created a standalone pack that does the following: If you are unwilling to edit
DarthMod multiplies the AI’s "thinking" time to prevent dumb moves. That’s great for challenge, terrible for your CPU. The result? The Ottoman turn takes longer than the previous 15 factions combined. empire total war darthmod ottoman turn lag fix best