then its not lagging.
lagging is either a gap between an action and a reaction, i.e. you press a key and nothing happens.
or
it is something you put on pipes.
it is not low frame rates or inconsistent frame rates.
describe your problem without using any terminology that you don't really know the meaning of, as that will make it a lot easier to help you when we know what is actually happening as opposed to trying to guess what you mean.