CPU Overload whe exporting audio mixdown in real time

Hello. This happened before with 8.5. Now with 9.5 worse than ever. Using Instrument and External Instrument track. Froze and rendered 7 tracks and it barely gets past one measure without stopping the export. Very frustrating. Plenty of ram and Mac activity monitor not showing excess.

What are your system specs? Could also be caused by a slow drive.