How to minimize MIDI delay while playing

How are you listening to the MIDI instruments?

MIDI is not "slow" (Ok, it is, but not how you mean.)

Most likely either your monitoring of the audio generated by your MIDI instruments is affected by latency, or your main audio output is shifted backwards because of PDC to keep all your audio data aligned with latency-inducing plugins.

I listen audio thru phones monitor output on MOTU828 MKII USB audio interface

Yes, but is the synth audio hardware direct monitored, or is it being monitored through Logic?

(This is nothing to do with the path of your MIDI signal, I'm convinced it's latency and audio related.)

The motu has a 'cue mixer' program.. Open that up and set the balance between, the instrument you are playing live, and the output of Logic.. Make sure your keyboard is in 'local control' mode. So that you hear what your are playing, and not the output of Logic being fed to your current midi instrument..

Make sure the output of Logic does not have an 'adlimiter' on it.. (it delays everything)

You could also go to core audio preferences and shorten the buffer as much as you can without Logic beginning to 'stutter'

Because The motu 828 (and most of the more expensive boxes) have a 'live input, no latency mode' setting. You should not have the kind of delay you are talking about..

One possiblity might be, that you have "local control off", so you are having your Midi travel from you keyboard, into Logic, and then sent back out. Temporarily shut off any plugins you have on which may be adding to latency. Shorten audio buffers too.

If you:
Create a fresh project with just 1 Software Instrument track and load an EXS24 with a Piano sound into that, is that still delayed?