srx - youtube performance - slow buffering

hi,

I am using srx220h2 at home. srx is connected to router (from ISP) via 1gig link. On srx were configured: VRFs, NAT toward Internet, zones and sec for traffic. One host is conected via other 1gig link. On this host I noticied that youtube performace is very bad. I have to wait (a few min) before film will be started (buffering is very slow). When my host is directly connected to ISP router I dont have this issue. Do you know what is a problem? 

root@srxA-00> show system processes extensive
last pid: 13427;  load averages:  0.11,  0.13,  0.10  up 9+23:53:14    22:41:19
130 processes: 15 running, 102 sleeping, 1 zombie, 12 waiting

Mem: 207M Active, 138M Inact, 1042M Wired, 160M Cache, 112M Buf, 425M Free
Swap:


  PID USERNAME  THR PRI NICE   SIZE    RES STATE  C   TIME   WCPU COMMAND
 1342 root        5  76    0   996M 63224K select 0 270.2H 98.44% flowd_octeon_hm
   22 root        1 171   52     0K    16K RUN    0 199.7H 81.93% idle: cpu0
   23 root        1 -20 -139     0K    16K WAIT   0 130:31  0.00% swi7: clock
 1325 root        1  76    0   114M 17360K select 0  83:39  0.00% chassisd
 1368 root        1  76    0 12452K  5832K select 0  46:20  0.00% license-check
 1330 root        1  76    0 28252K 10676K select 0  31:53  0.00% mib2d
    5 root        1 -16    0     0K    16K rtfifo 0  30:43  0.00% rtfifo_kern_recv
 1332 root        1  76    0 20300K  8640K select 0  29:12  0.00% l2ald
 1345 root        1  76    0 50332K 15468K select 0  23:22  0.00% jdhcpd
 1353 root        1  76    0 15988K  3684K select 0  21:48  0.00% shm-rtsdbd
 1346 root        1  76    0   118M 86120K select 0  18:11  0.00% authd
 1364 root        1  76    0 17392K  8008K select 0  15:14  0.00% utmd
   25 root        1 -40 -159     0K    16K WAIT   0  15:13  0.00% swi2: netisr 0

root@srxA-00> show chassis routing-engine
Routing Engine status:
    Temperature                 43 degrees C / 109 degrees F
    Total memory              2048 MB Max  1106 MB used ( 54 percent)
      Control plane memory    1088 MB Max   500 MB used ( 46 percent)
      Data plane memory        960 MB Max   614 MB used ( 64 percent)
    CPU utilization:
      User                       4 percent
      Background                 0 percent
      Kernel                     5 percent
      Interrupt                  0 percent
      Idle                      91 percent
    Model                          RE-SRX220H2-POE
    Serial ID                      ACKA2070
    Start time                     2016-04-14 22:48:35 UTC
    Uptime                         9 days, 23 hours, 53 minutes, 24 seconds
    Last reboot reason             0x200:normal shutdown
    Load averages:                 1 minute   5 minute  15 minute
                                       0.05       0.12       0.09

root@srxA-00> show system memory
System memory usage distribution:
       Total memory: 2097152 Kbytes (100%)
    Reserved memory: 1044220 Kbytes ( 49%)
       Wired memory: 1067140 Kbytes ( 50%)
      Active memory:  211716 Kbytes ( 10%)
    Inactive memory:  141504 Kbytes (  6%)
       Cache memory:  163388 Kbytes (  7%)
        Free memory:  435944 Kbytes ( 20%)
Memory disk resident memory:   44972 Kbytes
VM-Kbytes(  %  ) Resident(  %  ) Map-name
   625680(59.67)   138316(00.00) kernel