what is best memcache por APC

I have two cachers installed on my server. Currectly i use APC 3.1.2 as a default cacher for vbulletin. But i use memcache for vbseo because my concern is mysql. Should i use only 1 cacher or i can use two more effectively I have 1 xeon 4 core 5520 CPU with 4 gb ram. If experienced one tell me i'll like it. For example, i use for vbseo cache as APC and vbulletin cacher as memcache. Or i should better use only memcache or APC for every possible place. I also use vb optimise plugin lite version.

I heard memcache better to be used at multi server solutions but not sure. APC maybe perform better.

I use a combination of memcache (vb) and xcache (vbseo/everything else)

What's the benefit of separating

vB (datastore) to memcache
and the rest(vBSEO/WP,Etc) to APC or xcache?

I've asked this before but never really got a definitive answer on the benefits of using both.

they basic concept separation is
a) cache db queries (memcache)
vs
b) cache php compile (xcache)

In my opinion, with a large board (more than 2 million posts) xCache is best choice. I've tried APC, eAccelerator, Memcached and xCache. After 3 years, xCache is my final choice. And for stable, remember not to use more than 256 MB RAM on any Caching software, if not, it will be un-stable.

@Brian Cummiskey
xCache can also be used for User cache (DB Queries caching).
I'm using xCache for both VBSEO, vBulletin Datastore, VB Optimise Pro (DBT) and php files caching.

Dihuta what version do you use xcache? and which php version?
I use 512 mb ram for my webmaster forum for APC but i'm goingto lower the shared memory amount. Thank you. It's really helpful for me.

I'm using 1.3.0. It's stable if I use < 256MB.
PHP is the lasted one, 5.3.3. Initial I want to use 1GB for Caching software but finally, I feel it is unstable and un-needed.

Note that Bigger forum should also think about using CDN for static files. Apache act like a girl when it serves too many static files request. And fortunately, VBSEO 3.6 is bringing these features to us now.

1TB - 40$ is very reasonable price for us.

Thank you. I use Cloudflare as CDN and i never seen my load over 1 Also i have hosting sponsor which pays the bantwidth. I know at high load apache becomes girly from my other web projects it make alot of log files if you have over 1 daily million uniques. You get 3-4 days 20 gb of logs..

So i plan to have at next nginx. My main problem mysql these days. I plan to buy an extra demon for it. I heard good things about it. I removed my apc and soon intalling xcache.