What your system admin means is that he is going to set up the Testing server so that it resembles the Production server as much as possible, if not exactly the same.
This is good practice to minimise defects that occur in one environment but not the other.
For any given server, there's the Hardware (could be VM), the OS, and the applications running on top of the OS.
If testing at a high application level, having the same application configuration on both environments would be much more important than hardware or OS configurations. But if testing at a low level or for performance testing (for example), hardware/OS configurations would become very important as well.
I always ask for the testing environments to be configured as closly as possible to the production environments, but this seldom happens. Quite often you find system admins or developers arguing that the differences in the environments won't cause any problems, when they often do.
I think it is good that your system admin keeps saying that he is going to configure the Testing server to replicate the production environment.