Now it looks like the download is sort of still going, but at a significantly lower speed-- we're talking going from 300Mbps to 30, and the display isn't updating-- the only indication that something's going on is that I see network activity in task manager, and when the unrar finishes, the progress bar and number of bytes downloaded suddenly jumps.
When it's unraring/repairing, it's downloading to RAM so it should still be full speed. It'll download till the cache runs out though so, once it hits zero the download stops. I still get full speed downloads while unraring because it's not going to disk.
I'm actually amazed that you can get anywhere close to 300 Mbps with USB Ethernet adapters. They're crippled compared to on motherboard cards.
Dirty connections errors aren't that unusual as long as they don't happen very often. Let me clarify and say they're not unusual for Astraweb. I never get them to Giga.
I was talking to Dex about this situation. There's a real reason the downloads are stalled when the cache runs out and that's because before this, the downloads would get way ahead of the unrar which worked out to be more unreliable. It means restarts were very expensive an error prone too. Downloading and unraring at the same some triples unrar time too.
I do think I might have an idea about how to permit the download to continue while not running too far ahead of the unrar. It would mean downloading the chunks and letting them get ahead but not assembling files till after the unrar finished. So basically it would be like using the disk drive as part of the cache when the cache fills up. It solves the restart problem and get ahead of unrar problem. Your unrars will still be made much slower. Maybe with SSD this is less of an issue today.