i had the same problem (with the st map)
to all of you with low specs that run RTW smoothly, i really hate you guys.
i have 2.4 ghz p4, 512 Ram. Raden 7500 mobile 32 MB, and my frame rate is so bad that it feels like i'm on aced when i play the game.
i ended up spending $800 on a new pc.
so to all you lucky people, i really hate you all. (i'm actually very jelous.)