Like most other software instruments, MSI can use a fair amount of RAM and CPU power.
Page 16 of the MOTU Symphonic Instrument contains details on conserving CPU power. Read through this page in the manually carefully so that you can understand how adjusting the following settings will affect performance:
– Reduce the polyphony setting to a value that still allows you to perform all notes.
– Turn off filters when not used.
– Shorten the amplitude envelope (especially ‘release’) to help reduce polyphony.
– Disable MSI’s reverb when not needed.
– Adjust the “hardware buffer size” in your host application – generally increasing the size will help.