Bandwidth Emulation availability without network emulation (NWE) driver
The Bandwidth Emulation is available without installing the NWE driver. To use this feature, you will need to go to SETTINGS | ACTIVE PROFILE | REPLAY | INTERNET | EMULATION and enter or ensure that the value is 0 for both the Latency and Packet Drop fields.
You will need to do this for the other profiles for the project if these profiles have non-zero values for either the Latency or Packet Drop fields. If the network driver is not installed and these fields have non-zero values, running tests under these profiles will cause an error.
This information can also be found in the online documentation here.
In summary, only the latency and packet drop emulation features will require the NWE driver.
In Silk-Performer 16.5 and later versions, a "Use network emulation driver" check-box is added to enable the latency and packet drop fields. The driver is still required but the checkbox makes this requirement more obvious.