Also did some benchmarking on my Macbook (with a SSD and memcached running on localhost):
Checking egw_cache_memcache:
0 checks failed, 100 iterations took 0.480 sec
Checking egw_cache_apc:
0 checks failed, 100 iterations took 0.025 sec
Checking egw_cache_files:
0 checks failed, 100 iterations took 0.826 sec
--> APC is by a factor of 20 faster then memcached, which is double as fast compared to files on a SSD
Used now by default, if function apc_fetch() exists and no
other caching provide is explicitly set in header.inc.php or egw_cache
class.
It's probably quicker on virtual machines, as it uses memory and not the
filesystem.