Harmony EFX, MIDI and Logic Pro 9.1.5

hi there,

i'm facing following problem quite often: if i use a midi track within logic pro 9.1.5 with harmony efx as an instrument, doens't matter if midi omni or midi channel, and an audio track as the side chain, it does work several times to record midi, but after some tries i get a logic error dialog, saying that the hard drive is to slow.

therefore i have to restart logic to use harmony efx again because if i want to record midi again or if i just play some midi notes, the complete audio stops and i just receive some clicking noises...

by the way i'm using the i onix u42s audio interface.

does anybody faces the same problem or have some advice or tips for me!?

thanx in advance

kind regards

stefan.