by VanessaE » Fri May 03, 2013 00:34
Of the mods you listed, the biggest suspects are Moretrees, Snow, Moreores, Glooptest, Gemstones, and Diamonds in that order. Each of these adds a certain amount of load to the engine's map generator.
Moretrees has to use Lua (by way of plants_lib) to evaluate where the trees should be placed. When it adds those huge trees to the map, it uses features in the engine, but do so stresses the engine's lighting and node placement code pretty hard. It can take up to about 3 seconds to fully populate a map chunk (80x80x80 nodes).
The snow mod does everything in Lua, from evaluation where the snow is to be placed to actually placing it, as well as growing the small trees and causing the occasional snowfall. I have not benchmarked this mod, but I'd guess at least a couple of seconds per chunk.
These two can be improved by way of further refinements and additional features in the engine code, which may or may not require rewriting those mods and their dependencies to suit.
Moreores used to do all of the hard work of placing ores in Lua - if your version of that mod is too old, you aren't seeing the benefit of recent changes in the map generator that allow for automated, C++-assisted ore placement.
Glooptest has the same issue, but I don't think it has been adapted to the new ore method. This mod is a dead project and is not recommended for use on new maps.
Gemstones looks like a dead project (last update was Dec 15, 2012) and uses the old method. It is also not recommended for use on new maps.
Diamonds have since been incorporated into the default game using the new ore method, but the external mod still uses the old ore generation code. Until an update is released to strip out the old code, it is not recommended to use this mod.