The game lags/skip frames at 1680x1050 resolution on my computer. However, this computer can play games like Crysis on that resolution at high settings without lag. Specs are 4GB Ram, 2.4GHz Intel Core Duo processor and Nvidia 8800GTX. I'm using Vista 64-bit.

1680x1050 has too much slowdown so I play at 1280x800. But even at that resolution there is slowdown sometimes. Any idea why this is/how to improve performance?

Close explorer.exe, taskmanager.exe, reduce the graphic details to minimum (black background, one layer of waves). People play without screenlags at resolutions like 1600x1200 or 1920x1200. Also, make sure your anti-virus isn't doing any real-time scanning while you play, close any programs that should not be kept opened during game-play (browsers, players).

Also, make sure you have the latest update (3.6.29.0), as I believe some performance issues were fixed there (though I might be wrong)

The game is rather taxing on the CPU, my Core 2 DUO e6750 (2.66ghz) can't spawn crates instantly on large maps without lag and I get lag/hitches when using a gradient background with the sky clouds and background etc. even on normal size maps. I play with no details enabled, the background debris and extra water layers just make it harder to rope and judge shots.

transparent team names also cause hitches no matter what detail settings or map size I use too.