Machine:
Gateway MT6452 laptop with:

* AMD Turion64-TL52 (X2)
* 1Gb RAM
* XP Pro SP2 with all current updates
* ATI Radeon Xpress 1150 graphics
Problem:
Game plays (with good (35FPS) to incredible (>250FPS) framerate), but graphics very jumpy, making it difficult to control.

Have also noticed that the game ran better under Vista Home Premium, which doesn't seem to be others' experience.

Anyone know a workaround or how I need to configure my graphics drivers to correct this?

Perhaps you should check that vertical sync is on; also known as vsync. It limits the frame rate to the speed that the monitor refreshes it's screen. It should limit your frame rates to something more acceptable, however the big slowdowns I don't know how to help you there, unless you are willing to lower some graphics settings to help keep things running smoothly if you really wanted to.

Also,

Try searching for the screen setting post on the forum, there is a registry setting you can put in that will allow you to set what your screen is and I think Killier made a utility to allow you to set it as well.

Make sure you are using the latest drivers for your video card which means looking for downgraded drivers if your system came with Vista installed.

You can grab the TM Screen mode Manager tool here:

http://www.omnilinkavstudios.com/treadmarks/main.php?page=BJS/downloads_Tools.php&group=BJS&uid=&

But I'm wondering if the jumpiness is due to lag.

Are you playing in multiplayer or single player mode?
If its single player, how many ai tanks?
If its multiplayer, what is your ping? which server are you playing on?
Do you have anything running in the background that is hogging cpu resources?
Did you try turning off the in-game music?

It can also be the audio drivers.

Possibly was problem with hardware, as the laptop I was using then (a Gateway MT6452, having ATI Radeon graphics system) has since died and been replaced with a laptop with nVidia graphics. The current laptop doesn't exhibit the problem, incidentally.