Poor Performance on VmWare

first of all sorry for late response and thanks for your answers.

sure i read the NetBackup for VmWare best practices but there was no helpful hint :(

I understand that it is hard to help here without having a detailed knowledge of our environment. But what i am wondering is, when i use "nbperfchk" and send a 32Gb file from our vmware environment to the media server i get rates of avg. 750Mbit/sec. This means the process is 50 times faster than the backup process. So should not be a network issue. 

I am really lost here :(

Are there any log files helpful?