You can find useful details in the Performance monitor window. Have you tried increasing the block size?
For example, for the common glitches caused by the CPU not having enough time to process the entire buffer:
- RT xruns would increase when the audio stutters
- RT longest-block (6.71ms in the screenshot below) would be larger than the maximum block processing time (10.67ms below)
- RT CPU would likely be on the high side
- Total CPU is not really relevant here