Those who have been playing IC2 2.0 & latest GT can be well annoyed by the almost complete lack of documentation for them (the GT wiki is being sloooowly updated and the IC2 wiki has absolutely no information about the latest additions).
The thread has a goal of documenting these by being intended to have small posts about their tips & tricks.
Rules:
1. Post here about mechanics/caveats/"undocumented" features of IC2 experimental and GT 4.x. No crafting recipes since all players here have been expected to install NEI long ago (especially GT ones). However, you can write how many raw materials you need to assemble a certain thing.
2. Questions are also permitted.
Examples:
1. Bronze Blast Furnace requires 1 iron ingot & 4 coal for 1 steel & 4 dark ash. It doesn't need any steam.
2. What's the Tin cable energy loss?