Frame Rate

Frame rate refers to the number of frames per second being displayed on your screen. Halo: Reach runs at 30 frames per second (fps) under normal circumstances, and any noticeable drop below that is massively harmful for a competitive map. These drops are known as "screen lag," "frame rate lag," or the euphemism "performance issues."

Forge World maps have been known to have problems maintaining 30 fps. Some of the most common sources of screen lag are object density, lighting effects, particle effects, and simply the number of objects on screen.

Object Density
Object density simply refers to the number of objects occupying a single space at once. Put simply, the more objects you use on your map, the higher your object density is, and the more likely it is that you will run into frame rate issues.

Lights
Lights are a major source of frame rate problems. The objects under the "lights" category in forge should be used only with the utmost care. Additionally, many objects have small lights built into them. These objects should be avoided in most situations.
 * Block, 5x1
 * Bridge, Large (x2)
 * Bridge, XLarge (x4)
 * Bridge, Diagonal
 * Bridge, Diag, Small
 * Corner, 2x2
 * Large Walkway Cover
 * Platform, Ramped
 * Railing, Small
 * Railing, Medium (x2)
 * Railing, Long (x2)
 * Snipers Nest
 * Wall
 * Wall, Double
 * Wall, Curved
 * Window, Double
 * Ramp, 2x2 Steep
 * Ramp, Circular, Large

Other Effects
Some other things are known to cause frame rate issues. Some of these include:
 * Focus Rifle
 * Shield Door
 * Forge World's Waterfall
 * Having camo
 * Splitscreen
 * Covenant Barrier
 * Z-Fighting

Testing for Screen Lag
Since screen lag is most commonly a problem in split screen play, that is the best way to test it out. Ideally, one would play full 4v4 games with at least 2 players on one box and keep an eye actively watching for screen lag, but this is not always possible. The next best thing to do is to plug in a second controller and run around with good camo, a sniper rifle and a bottomless clip AR. Test all sight lines from a variety of positions while strafing. Fire that bottomless clip AR to generate lots of sparks, as the particle effects stress the engine. Additionally, test scoping in and out with the sniper while strafing from a variety of locations.

If your map passes this test, it still might not be perfect. It is always best to ask for many second opinions and play many games on your map before letting yourself be satisfied with its performance.