Thanks for the sugestion Apathetic, i installed APC to start, now is not a peak hour but after install and configure APC (php.ini and w3 total cache) seems that cpu load is arround 0.80-0.90 , decent for two core cpu VPS.

Go to write here steps, because can help newbies like me.

Was easy to install APC using cPanel/WHM, steps for cPanel (v11.32.3):
Software >> Module installers >> PHP Pecl >> Search "APC"
Click install and wait until finishes. Then you need to edit php.ini (/usr/local/lib/php.ini) and add line:
Code: 
extension="apc.so"
I added the line after text:
Code: 
; Directory in which the loadable extensions (modules) reside.
extension_dir = "/usr/local/lib/php/extensions/no-debug-non-zts-20090626"
;extension="eaccelerator.so"
extension="apc.so"
Check that into "extension_dir" exists file "apc.so".

Restart Apache.

After that the apc should be enabled, you can test with a phpinfo file (if APC appears on the config file it?s working):
Code: 
<?php phpinfo(); ?>
You can do some finetuning of the APC config (adding lines to php.ini), but depends on your needs and VPS resources (my settings for a wordpress into a VPS with 1GB Ram):
Code: 
apc.shm_size=64M
apc.ttl=7200
apc.user_ttl=7200
apc.max_file_size=2M
I?m new using APC, perhaps i miss some settings, but is what i achieved into a fast APC documentation reading.

For sure after install APC cpu load decrease but RAM usage increase arround 80/100 MB in my VPS.

About install Varnish seems a hard task (not for newbies) install it on cPanel/WHM unless i use a payed cPanel/WHM plugin