See these threads for background:
http://www.vmware.com/community/thread.jspa?threadID=58736
http://www.vmware.com/community/thread.jspa?threadID=60462
I have setup a Yum repository with a custom kernel compiled with HZ=100 for CentOS 5. This kernel improves performance when running multiple CentOS guests on a single VMware Server.
These kernels have only have minimal testing so be cautious using them. Due to build problems the kernel modules are \_NOT_ signed.
You can find the repository here with CentOS 4 and 5 kernels:
http://vmware.xaox.net/centos/
Download VMware.repo into your /etc/yum.repos.d for easy access.