Thanks for your comments guys.

I have been playing around with the physics engine, which seems to be linked into the FPS very closely, and performance between full and window modes is very different. In window mode the FPS can run very high, 300-400fps with not a lot going on screen, and yet the exact same view in window mode can only reach 69fps.

To get some kind of consistancy between full and window I would need to use some FPS MAX and Lock FPS options based around this 70fps.

As far as I understood this, it was due to a limitation in XP for TFT monitors, but from what ulillillia says, this also happens on CRT monitors???

In short, if the 70fps problem for TFT's is real, this surely means you either have to fix all games to not run faster than 70fps, or detect that its a 70fps limited machine and either warn the user or inform them it will not play properly? Especially when using physics. My recent experience shows that fixing FPS in this way can lead to some strange behaviour and speeds of movement when things get busy on the screen....

I didnt really want a debate on what is the best monitor, simply to find out if this 70Fps problem was a bigger problem than i thought. From the sound of what you guys say, the 70fps is a genuine problem and there is no fix for it....

Very worrying as our concept proof is a physics based title, and it needs to perform the same on all PC's, and to limit all titles to 70fps max will create a plethora of problems for us.

Is there an alternative engine that doesn't suffer from this problem? I presume there is no way to fix it with GameStudio?

TIA guys