What is the disp cost?? :-)

It's one of the metrics used to tell how hard the track will be for your graphics card to display it.

Different blocks have different display costs. In other words, the cost of how much it takes your graphics card to display the geometry and textures of that block. The more complex the block, the more your graphics card has to work to show that block, so the display cost rises.

On track pages when you see "Disp. Cost" this is the same as the number displayed in-game at top right in the track editor. Nadeo has set some soft limits on the Display Cost for tracks. If you go over 10,000 the number turns yellow (if I remember correctly) and you get a notification popup that you might want to reduce the number of blocks to make the track smaller. If you go over 15,000, the number turns red and you should really think of reducing the number of blocks.

You can ignore these limits, but the higher you go, the more likely that people won't be able to play your track. Normally this only becomes an issue with endurance tracks, or people who go completely bananas building complex scenery.

^ or rpg maps good explanation

If you do happen to go over 10,000 or 15,000 for you display cost, make sure that it is spread around on the map. If you don't have too much scenery all in one place, people playing it won't get as much lag (usually).