The performance you get from KRISTAL will depend to a large extent on your audio hardware and its drivers.
Generally, audio devices can be divided into two categories: those that support 'ASIO', and those that don't.
ASIO (Audio Streaming Input Output) is a proprietary 'industry standard' for music applications, developed by Steinberg Media Technologies GmbH. It provides multi-channel audio I/O (input and output) at very low latencies and high sample rates.
In order to take advantage of ASIO, you need specially-written ASIO driver software for your audio hardware. This should be supplied by the manufacturer - if in doubt, check their website for updates.
Note: the I/O ports of ASIO devices can be accessed via MME (see below) as well, meaning that they appear twice in the KRISTAL Audio Engine menus. However, ASIO and MME devices used together in a project will not be 'in sync'!
How to disable ASIO/MME devices
MME (Windows Multimedia Extension) is the standard built-in audio driver architecture of the Windows Operating System.
Any audio device can be used with MME: no special driver software is required.
Because of its limitation to two-channel stereo audio, and high input-to-output latency, MME is not really the best choice for music applications.