I doubt xcache is going to clear your high load issues, your server needs to be checked for the other issues its having & optimized as well.
Code:
[xcache]
xcache.shm_scheme = "mmap"
xcache.size = 96M
xcache.count = 4
xcache.slots = 8K
xcache.ttl = 3600
xcache.gc_interval = 300
xcache.var_size = 16M
xcache.var_count = 4
xcache.var_slots = 8K
xcache.var_ttl = 1800
xcache.var_maxttl = 3600
xcache.var_gc_interval = 300
xcache.test = Off
xcache.readonly_protection = Off
xcache.mmap_path = "/dev/zero"