Xcache Optimal Settings

[Firyou]

Hello, I was wondering if anyone has any recommendations on optimal vbulletin 4.2.0 Xcache settings? My server is a VPS with a AMD Opteron(tm) Processor 6376 Dual Core and 4GB of ram. My current Xcache settings are:

extension="xcache.so"
xcache.admin.enable_auth="off"
xcache.admin.pass=""
xcache.admin.user="mOo"
xcache.cacher="On"
xcache.coredump_directory=""
xcache.count="2"
xcache.coveragedump_directory="/tmp/pcov/"
xcache.coverager="Off"
xcache.gc_interval="0"
xcache.mmap_path="/dev/zero"
xcache.optimizer="Off"
xcache.readonly_protection="Off"
xcache.size="64M"
xcache.slots="8K"
xcache.slots="8K"
xcache.test="Off"
xcache.ttl="0"
xcache.var_count="2"
xcache.var_gc_interval="300"
xcache.var_maxttl="14400"
xcache.var_size="3M"
xcache.var_slots="8K"
xcache.var_ttl="7200"