Performance Slow on VM

We have same CPU / Memory (OS and database) configurations for one of the database on a VM and Physical host. Clients are complaining that performance of VM takes the double time to process the same number of records compared to Physical. I do agree that Physical hosts are better than VMs. But the clients are with 10-20% performance differences, but not the 100% performance degradation. (For example: One Batch process on VM takes 1min, where as Physical takes 20-30 seconds).

Is there anything we can look into at Oracle (database) side ???

FYI: Both VMs are running on Windows OS.