Strange lag

[xenos60]

I have been playing MIITW and the Britannia expansion since Christmas day. I was able to run the game on highest settings ,even during full sized battles. A week later I Downloaded and installed the For King or Country modification, the came continued to work as before (and the mod is excellent). Another week later I installed the last Darth mod and the Renaissance mod, It continued to work for another week. After those three days I was able to run full sized pitched battles on highest settings, but begun to experience extreme lag during siege battles, even with lowest settings. This problem affected all mods.

I am running 1.03.
Aside from the mods, no changes have been made to my gaming computer since the initial intillation and the gaming computer is not connected to the internet.
I am running an 80gigabyte hardrive with 1.5 gigabytes to spare. I have 1024 megabytes of ram and a geforce 6800GS. The screen resoulution is 1024x768. None of this has been changed.

[Squid]

Not enough spare space on your HD. In most cases it is recommended to have at least 10% free space (20% is probably ideal) for virtual memory and other needs (such as moving files around during write or defrag). With 1.5G free and your virtual memory probably greater than 1G any time a read/write has to occur on the HD it will be significantly slower.