So you are seeing CPU performance issues and you increased the CPU count on your Guests, thereby increasing the vCPU over commit on your hosts, increasing the possibility of increasing CPU ready time and increasing the risk of CPU timeouts.
Return the CPU count on the VM guests to what it was originally.
What is the loading of your hosts in terms of CPU?
What is are the guests saying their CPU utilization is?
Read the following KB articles on CPU performance
Troubleshooting ESX / ESXi virtual machine performance issues
Determining if multiple virtual CPUs are causing performance issues
and the following PDF