leap 42.1 + xfce + laptop

launch FireFox and open urls in the varios tabs ( youtobe, sites with flash player and etc ).

openSSUS | Log out | Hibernate
wait 60 min
press power on
System UP an FireFox freeze..
in the iotop i see 98% utilization io from the Firefox...
wait 3...7 min ....after this i can use FireFox

Any body have this problem ?
Pleae help me.