fitgirl repacks attempt to stress your cpu/gpu to the maximum and try to overheat your beloved PC, by making the data for the game astronomically compressed to the point where the decompression time can actually take longer than the time to download the original crack on USENET by as much as 4-8x.
If you have USENET, don’t even bother. If you have unlimited Data on your ISP, just torrent the un-“packed” version. You will thank me in the longer time. Its not worth it in most cases.