I had by the use of N1MM+ with keying via the Winkeyer emulation sometimes a unacceptable delay detected between the command and the start of real keying.I make also some delay measurements in CW with keying via CAT-ports and via Winkeyer emulations ports.
Principal is always a delay to expect, because Windows is a multitasking OS. The communication via a serial port has a low priority in Windows. There will always be some delay.Because CAT and Winkeyer both use a (virtual) serial port, I expected about the same delay on CAT and Winkeyer. But there where big differences between both methods.There where also differences between the ports at the same moment.
By use of the Winkeyer emulation was in my situation the shortest delay of the start about 170 ms and the longest delay about 700 ms (repeated difference between two Winkeyer emulation ports in the same test situation!)
By use of CAT-ports was the delay of the start between 0,5 and 2 ms.
I had the measurements repeated by different starts of the PC. After every start-up the results changes every time.
The delay in CAT is minimal.
The shortest delay by use of the Winkeyer emulation is acceptable, but if the delay is to high, You can try an other Winkeyer emulation port or try a new start-up.
In general: I prefer CWX.