I am downloading to my User Shares, but they are all set to use my Cache drive which is an SSD. I actually bought an SSD because i thought that was the issue. Still, no issues with 6.4.1. Or VERY rarely and for a shorter period of time, newer versions I have to paus the downloads to get it to catch up.
Glad It works for you, I still think It's a bit overkill to have to create a VM to download things to a fileserver. I really just wish I knew what the issue could be with all the newer versions of Unraid that says the disk overload when the older version don´t.