TSM client restore files too slow

Hi,
please anybody can help me problem with my tsm client ? I explain situation:

I have tsm Server Version 6, Release 2, Level 2.2
Client Version 7, Release 1, Level 0.0

Media server redhat 6.5 where is client :
6core Xeon cpu, 64G RAM, 2x10Gb ethernet bonded to bond0, 2xinfiniband(2x4x10Gbmelanox card) bonded to bondib

On this media server i have mounted nfs volume via infiniband from another server with options :
rw,sync,bg,hard,nointr,rsize=1048576,wsize=1048576 ,proto=tcp,vers=3,timeo=600
and tsm client that archive and retrieve files from nfs mount. This files are 50G and more in size.

Now i perform archive 50G to tape from local hard drive of media server and then i restore this file to nfs:
Backup speed 130Mb/s, restore speed 114Mb/s

But when i backup file from nfs to tape and then restore from tape to same location nfs:
Backup speed 130Mb/s, restore speed 4Mb/s.

Any sugestions what is wrong ? I dont use compression or deduplication. Any parameter in dsm.sys like tcpwindowsize, diskbuffer dont help. I use lanfree backups. Storage agent and client are both on same linux server. I always see one thread of all 24 threads of cpu running on 100% when restore files that was backuped from nfs.
Thank you all very much.

kernel parameters:
#sysctl -w net.core.rmem_max=134217728
#sysctl -w net.core.rmem_default=134217728
#sysctl -w net.core.wmem_max=134217728
#sysctl -w net.core.wmem_default=134217728
#sysctl -w net.ipv4.tcp_rmem="8192 87380 134217728"
#sysctl -w net.ipv4.tcp_wmem="8192 87380 134217728"
#sysctl -w net.ipv4.tcp_mem="6093984 8125312 32777216"
#sysctl -w net.core.netdev_max_backlog=262144