Terrain Speed

Hi there, I''m just wondering how much time (per frame) most games use for creating the terrain only.. In my game It''ll run at 58-62fps but if I take out only the terrain rendering code it''ll run at 125fps. Is that a normal ratio? By the way that 58-62 fps is without units, just the map, however, I''m running in 800x600@16bpp and I''m using a system memory backbuffer so that I can store all my graphics in system memory... So I believe I''ve acomplished something pretty ok... By the way my target system will be a 400Mhz machine I think and I''m running a 533Mhz machine so 45 fps on a 400 wouldn''t be so bad? Anyhow any opinions on how much time to spend rendering the terrain would be great! Thanks, Ben P.S. It''s re-rendering *ALL* the terrain each frame, which is a grid of 37x11 isometric tiles. So 407 tiles, each tile is 68x33 so essentially your blitting a 956x956 sized surface (407 tilesx68x33=913308pixels ==> sqrt = 956) And because of the nature of the blit (Using MMX, I think?) a transparent pixel is no faster than a normal pixel.