TYPO3 Core

If you have many files in a page branche they are going to be exported as well. I guess that tx_impexp loads them into memory and finally puts aut the T3D file.
The import/export functions have to be rewritten for TYPO3 4.2.

Still experienced large memory-consumption in 4.5.x lately. When exporting a large tree that can easily outgrow "reasonable" limits. Lately had a website and tried to export with 1GB RAM. Needed to bump it to around 12GB to finally get an export. (Okay, which failed on import then - but that's another story.)

Also even taking into account all files (graphics) on the filesystem would have been a lot less than 2GB. So I assume they get copied around in various places, serialized or whatever.

Splitting exports into multiple parts sometimes just isn't an option because of dependencies between objects and IDs.

Patch set 2 of change I3e690eea1a079ed6cadd548230afc405e005b115 has been pushed to the review server.
It is available at http://review.typo3.org/2610