It is likely you saved your playback configuration when instrument patches were loaded.
To fix this, go to Play > Playback Devices.
Click to select each instance of Kontakt Player and click "Show".
Unload all patches.
Go to Play > Playback Devices. Click "Audio Engine Options".
Try different buffer sizes. If your problem is CPU overloading, increasing the buffer should help.
If the problem is latency, then lowering the buffer size will help.
3) Try the Sib forum. You will probably get more results there.