I have noticed that the scripts execute more slowly on a local install than they do over the Internet. The larger the script the more noticeable the lag is. I am on an Acer 5733Z laptop with a P6100 2Ghz Dual Core processor, although like most laptops it has a 5400 rpm 500 GB hard disk so I guess that could slow it down a bit.
I would think that these scripts like Word Press and WikiMedia would run very fast locally since they run fast most of the time on the Internet.