Troubleshooting Virtual Server Performance Issues
If you are having performance issues on a virtual server, check your server event logs - if they show SPP (software protection service) is scanning around the time of the issue, this may be a known problem.
We found the below information that could be of help:
From this link, the following recommended change is the most relevant part – this could actually have a negative impact though, so if your users complain performance is worse, it's best to change it back!
Make the following changes in the configuration of the SQL-instance
1.Open Properties for the instance in Management Studio.
2.Go to the "advanced" tab.
3.Change the option for maximum parallelism from 0 to 2.
4.On the memory tab, change the maximum memory for the server to 1792 MB.