basically in blockland bricks are rendered on the client sided as pacnet said, so if you are hosting a server and your getting brick lag this could potentially cause server lag because you are slowing down the rate at which you are sending server information to your clients, but if you are hosting a dedicated server, the dedicated client doesn't need to render the bricks so it will not get any lag and slow down, bricks are probably the least laggiest thing in the game so you don't really need to worry about it