npc saving cause lag

[ghost]

I've 9 NPC (3quester and 6 normal) with 16 quests.

[INFO] [Citizens] Saving npc files to disk...
[INFO] [Citizens] Saved.
[INFO] Connection reset
[INFO] Connection reset
[INFO] Connection reset
[INFO] Connection reset
[INFO] /88.121.80.61:52794 lost connection
[INFO] /89.158.82.203:55396 lost connection
[INFO] /78.248.112.160:56374 lost connection
[INFO] /78.119.15.185:52935 lost connection
[INFO] /109.89.147.16:57975 lost connection
[INFO] /82.242.84.29:52779 lost connection
[INFO] /82.241.75.212:50260 lost connection
[INFO] /90.45.236.152:56438 lost connection
[INFO] /81.66.173.160:60940 lost connection
[INFO] /82.245.63.108:50989 lost connection
[INFO] /78.159.16.121:55602 lost connection
[INFO] /109.218.183.148:53000 lost connection
[INFO] /90.33.146.206:57037 lost connection
[INFO] /78.236.74.197:52041 lost connection
[INFO] /78.119.15.185:52953 lost connection
[INFO] /78.248.112.160:56376 lost connection
[INFO] /74.58.155.22:29175 lost connection
[INFO] /77.204.83.41:52142 lost connection
[INFO] /95.136.156.150:54017 lost connection
[INFO] /81.66.173.160:60949 lost connection
[INFO] /95.136.156.150:54018 lost connection

etc....