P4 1.7Ghz
256 RAM
GForce 4 MX 420
I get 300 FPS when 0 nodes and 90 FPS when all the screen is full.

AthlonXP 1.67ghz
512 DDR RAM
Windows XP Pro
GeForce2 Ti

0 Nodes: 444 fps
134 Nodes: 144 fps

Not bad, you should maybe look into fog depth cueing to help reduce the tile popping you see as you move based on your "render tiles close to camera idea" (which isn''t a bad idea, but depth cueing will improve it visually)

Have you also tried looking into terrain LOD with either ROAM or Rottger?

I don''t know how fancy you want to make your terrain engine but just some performance feedback and design tips that hopefully help ya out! =)

Good job,

~Graham


----
while (your_engine >= my_engine)
{
my_engine++;
}