Performance issue - excessive memory usage - nested field collection

Hi,

I have a big performance issue with field collection.

I have a content type Shop with a field collection reference to country. The field collection country have a field collection reference to city.

Its works fine but when I have many countries an cities the php memory usage increase dramatically (more than 100 MB just to load my form !!!) ...

I am looking for a technical solution to decrease the PHP memory consumption with field collection (patch, caching system or anything else ...).

I already use APC for PHP and some over system tweaks but the php memory usage still very high ..

Any ideas ?