I've thought about this a lot over the years. What you're asking is, can we accurately emulate our own universe inside our own universe at greater than 100% speed? If so, it would allow us to build a type of space-time machine where we could visit any location at any time.

I don't think it is totally inconceivable. It is definitely possible that there are hacks such as compression that would allow a simulator to run at above 100% speed. It also might not need to be 100% accurate -- we might find that running below that threshold still produces an output that is practically indistinguishable from the real events, yet allows it to run.