I downloaded the demo available on your website (TerrainDemo1.zip).
Runs ok at 1024x768x32, fullscreen, no VSync.
I got an average fps ranging from 150 (at the starting point) to more than 210 (when approaching the borders).
Considering that my sys specs are a bit low (PIII 1 GHz, 512 RAM, GeForce3 Ti 500, Win98se), I say you guys have done a great job!
When I switched to wireframe a few questions raised on their own...
How much distance did you put between vertices? 1 Unit?
Considering the textures you used, how would be best converted the distance that separates two vertices in your demo, into a real-world length measure? (example: 1 Unit = 1 Meter)
How far is set the far clipping plane in your demo?
Finally I noticed a weird... trembling... happening along the landscape borders, far away, where the landscape is supposed to fade out because of the fog.
It looked like Z-fighting at first, but switching to wireframe showed that some parts of the landscape edge (far away from my position) were being drawn and then not drawn. This thing happened continuosly, as if two slightly different scenes were being rendered at intermittence :huh:
Great job anyway! Regards.