30-35% is where it downloads the majority of the 4.5gb, so that will take the longest. I've been getting occasional reports of it running slow, but every time I test I get at least 200mb/s out of my 400mb internet. Hopefully I can figure out what's happening and fix it before 0.60.
Part of it is also your cpu speed, and distance from the server (US based). So if you have a slow cpu it can slow the download. I have a GPU version I am testing to see if that will improve the performance.