H - Sorry you have had a problem. This is not a site issue but possibly an experience you have had at one time or another due to network or other problems?
The site is consistent in the file links - so one file will always download at the same speed as any other file and of course the download speed will sometimes be better at at some times depending on site traffic and other things on the net. However as a member, logged in, it should be very rare that you get speeds as slow as you mention- I have never experienced that when testing or downloading from our servers.
For now I suggest you 1. Make sure you are logged in as a member when downloading (not a forum member - that is completely different) . 2. See if you experience the same problem again & if so can you give a link to a page or links where you are getting one file at 300 & another at 30? We can then look into it.
Thanks.
Many thanks for your support.

Simplicity is the ultimate sophistication. – Leonardo da Vinci