MRCC 880, as with all MIDI routers that must process incoming MIDI data, will add a negligible amount of latency. Typically, 1-3ms, depending on the MIDI message. 1ms is the theoretical minimum delay possible when sending to a MIDI 5 pin DIN port at 31,250bps.
Latency and jitter when using USB MIDI on the Windows OS will be typical compared to any other USB MIDI router. That is, acceptable for most use cases. If you require extremely tight MIDI timing for professional audio or movie production when using a DAW with Windows OS, you will need to circumvent the latency introduced by the OS and the DAW itself. This can be done with a clocking device that uses an audio "click track" and a plugin to get around the latency and jitter caused by the computer. One such device is the ER-M MultiClock, but there may be alternatives, do your research.
If you find that adding MRCC 880 is causing much more latency than another USB MIDI interface, then you should contact our customer support team for help in resolving the issue. A common cause of high latency is a MIDI feedback loop. It's also good to eliminate all but one clock source.