I really recommend you use the VMXNET3 virtual adapter and is possible to change the virtual adapter that virtual machine where your vCenter is running without problem, and one of possible ways to do this is:
1) add a VMXNET3 virtual adapter to your vCenter virtual machine;
2) connect to vSphere ESXi host where vCenter virtual machine is running and connect to the vCenter virtual machine console;
3) stop the vCenter services, remove the IP address from the old (E1000) virtual adapter and assign the IP address to the new VMXNET3 virtual adapter and then restart the vCenter services;
4) check if everything is working and then remove the old E1000 virtual adapter from vCenter virtual machine.
---
Richardson Porto
Senior Infrastructure Specialist
LinkedIn: http://linkedin.com/in/richardsonporto