Only sync once every second. Also:

Fixed some indentations

init.lua

@@ -92,25 +92,27 @@ end)
 
 dofile(modpath.."/callback.lua")
 
-local stepnum = 0
-
 minetest.register_globalstep(function(dtime) return matrix.step(dtime) end)
 
-function matrix.step()
+local stepnum = 0
+local interval = 1
+local counter = 0
+
+function matrix.step(dtime)
   if stepnum == 3 then
     matrix.connect()
   end
   stepnum = stepnum + 1
-
-	if not matrix.connected then return end
-
-	-- Hooks will manage incoming messages and errors
+  counter = counter + dtime
+  if counter >= interval and matrix.connected then
+    counter = counter - interval
     local good, err = xpcall(function() client:_sync() end, debug.traceback)
     if not good then
       print(err)
       return
     end
   end
+end
 
 function matrix.connect()
   if matrix.connected then