I have a site with high server load this is a message i got from my host ive out grown my vps

When I first went to the site to troublshoot it was locked up once again
with the memory graphs maxed out. I restarted it and watched it for over
2 hours until the usage slowly climbed to 1500, looking to be on a steady
trend up. There are currently 81 live processes under your free**** user
typically using 15MB of RAM each. That would be 81 processes with 101
connections. It seems like there is likely a lot that could be done to
cache your code so that PHP processes aren't triggered to eat up RAM and
efficiently die each time they are triggered b a page load. I would
suggest auditing your sites code to make it use caching so so many
processes aren't spawned.

What server do you recommend?