That's a good point, but the fact that all Turing machines are equivalent (and the fact that the equivalence is purely mathematical, and does not rely on any laws physics) implies that computers in ANY universe would be similar to ours. At least in terms of what it can compute. Even if the laws of the parent universe made their computers dramatically faster than ours, you would still expect that they would choose our universe's laws of physics so that they were relatively easy to compute, so as to save CPU time. That doesn't seem to be the case -- it takes us a supercomputer to accurately simulate a volume a fraction of the size of a proton. Of course this doesn't prove anything -- it's possible that computers in the parent universe are so ridiculously powerful that even simulating a trillion galaxies is just a drop in the bucket -- but IMO it is suggestive.