It's sometimes a crap shoot with archive.org. If you notice, different shows are stored on different servers. So sometimes you'll get a show from audio22.archive.org or audio24.archive.org, etc. It all depends on the server you're currently downloading from.
Even still, sometimes some servers are really, really, really slow. Do you know which one you were dl'ing from? I know that there are some servers that are smokin' fast and others forget it. You might as well go back to B&P.