Windows 7 x64
Broken: 2.79 testbuild 2
Short description of error
After rendering a scene with cycles and a lot of textures, memory usage is higher than before rendering. If the file is saved after rendering, Blender will take as much memory on opening the file than after rendering (in attached file, 2.2GB of memory for a cube vs 109MB before rendering.
Exact steps for others to reproduce the error
in the default scene, switch to cycles and append the cube from this file:
It uses 109MB memory. Hit F12, now it uses 2.2GB.
It looks like the persistent data option has been activated and the textures are cached, also the option is deactivated.