Low TPS and LAG

Hi. My server has 6GB, i7-920 and 100Mbps connection. TPS is low and server is lagging like hell.

Code:

Linux alpha-1 2.6.32-279.14.1.el6.x86_64 #1 SMP Tue Nov 6 23:43:09 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
java version "1.7.0_09"
Java(TM) SE Runtime Environment (build 1.7.0_09-b05)
Java HotSpot(TM) 64-Bit Server VM (build 23.5-b02, mixed mode)

Currently is 51 players online and TPS is 5-10.

Code:

Uptime: 18 minutes 35 seconds
Current TPS = 11.573528
Maximum memory: 6,371 MB
Allocated memory: 2,939 MB
Free memory: 938 MB
World "world": 10,292 chunks, 3,354 entities
Nether "world_nether": 0 chunks, 0 entities
The End "world_the_end": 463 chunks, 10 entities

Plugins (30): ChunkFixer, WorldBorder, NoCheatPlus, WorldEdit, Websend, AutoGamemode, Vault, PermissionsEx, CombatTag, LWC, WorldGuard, ColoredTablist, AutoMessage, CasinoSlots, AuthMe, HawkEye, UG, BKCommonLib, BanManager, ProtocolLib, Modifyworld, StopThatLag, Essentials, Jobs, ChatManager, InSigns, EssentialsSpawn, CreativeControl, NoLagg, ChestShop
Version: This server is running CraftBukkit version git-Bukkit-1.4.6-R0.3-b2586jnks (MC: 1.4.6) (Implementing API version 1.4.6-R0.3)
I have installed Multicraft, so I have default Multicraft command to start server.
I will write more information later...

 

Offline mode?

 

Yes

 

Then no support for you sir. Offline isn't supported here.