High disk utilization on NetApp self-encrypting disks using snapmirror

Does NetApp self-encrypting disks increases the background scanning process (such as disk deswizzling, block reclamation..etc) due to encryption compared to non-encrypting NetApp disks. We are experience high reads on the disks which has snapmirrored destination volumes due to deswizzling process. Both snapmirror source and destination storage has self-encrypting disks.  The CPU  usage is low (< 30%) and Memeory usage is also low. Due to business requirements, we have aggressive snapmirror schedule (every 15 minutes) and the updates between the schedule are low ( > 500MB). 


But after every update, we see disk usage will shoot up to 100% and on stait output, we see the 300+ disk iops on 10k rpm drives.


So my question is does NetApp self-encrypting disks increases disk background scanning process due to encryption as it may not be updating few changed blocks after snapmirror update process, but entire blocks due to encryption.