Compellent top speed but no writes in taskman and perfmon on Compellent Sc5020

Hi
we have made a vm on a xen server 7.6. we give the vm one network card an configure i to a fault domain to our sc5020 compellent Storage. We creates two volumes on the compellent. We create server and configure mpio on the vm with Win 2019 Server. We make the reg keyes as described in the best practice from Dell Compellent Windows Iscsi docu. We get 1,2 GByte/sek from one Volume to the second one but no writes in taskmanager and on the storage. Both Storages are on 10Gbit Lan without jumbo because jumbo frames are not supported at vms on xen Server.

why whe dont see writes on taskmanager and perfmon? And any writes on the storage. The speed is fantastic. But no writes in task man? We cant explain this. 
please help.

thanks

regards RoBudus