It's the classic lag issue report due to the new tekkit server. Found something but not sure how it would help. When I opened the server from the batch window ( that black console) as usual, for the external client was a lot of delay. They would have block break delay, or open a chest after about 5 minutes after they right-clicked on it. But they would walk just fine, without lagging around. However, when I opened the server from the jar file, the lag issues dissapeared but with it, all other non-vanilla items dissapeared from chests, my house and not sure but I think from mines too. They still apeared in NEI, and could be spawned. The lag sure comes from a mod. Also Java 7 Update 21 didn't changed anything.
