I run a x1650 Pro (512 onboard) and an Athlon 4200 (Dual 2.2 Ghz) with 2G's of Ram. Running ROW with graphics maxed out I get no slowdown in major convoys. Although - I noted your running alot higher res than I - being "old school" I run everything at 1024x768 still (heck I remember balking when everyone told me to ditch dos - I still have my 6.22 disks! - nevermind rez changes.) Remember that the higher the resolution -the harder the pc and vid processor have to work - which could be your bottleneck. Try dropping the resolution down would be the first thing I would look at doing - the true visual difference isnt major and the card your running should be perfectly comfortable with a "base" resolution like 1024x768. *When you do the math your actually asking the vid card to do what - about 25% more work pixel wise with that resolution...*
The second thing is to make sure your not running alot of stuff in the background. There are a number of process viewer apps out there - find one and kill everything you dont need. Its amazing the stuff that runs in the background that just sucks up CPU cycles. Once you know what you can kill and what you can't msconfig and the regedit app are great to get rid of the extraneous drag. Use some common sense - disconnect from the internet (ipconfig /release works great for DHCP machines) and kill your firewall and antivirus stuff temporarily - but make sure they are back up and going before you reconnect (ipconfig /renew in case you needed it)
There are a few other tricks - but these should help get you started.
