Thanks for the answer. I wasn’t sure If I needed to change the write to wp-content/w3tc/pgcache/ to 777, so I guess I can change it back to 755.
I am using a VPS. So will I be able to install APC? And what is SHM size, and how to adjust it.. what are the proper parameters etc..?
How can I verify that PECL Memcache PHP extension is installed? I am running debian (is the command something like memcache -v ?).
Can you refer me to any tutorials on how to install APC or memcache?