CPU utilization is 33% at 20 sec buffer, 16% at 10 sec & 13% at 6 sec. All these buffer settings cause stuttering. Also copied the SACD ISO to a local HDD from the NAS (at 110MB/sec), but it did not make any difference to the stuttering.
Does the same thing on 2 x PCs with different setups (1 running v19.0.163 and the other running v20.0.10), both Core i5 (1 is 2500k, the other is 4590s)