Assuming that you didn't see crashes at these speeds before upgrading, and assuming that nothing has changed on your system, and assuming that this applies to any and all downloads, etc etc, I'd follow Ascathon's advice and do a clean reinstall - removing any crap from your user directory, re-adding any antivirus or firewall exceptions, etc. Hard to know what else to suggest without any more specific information ...
Is it only cache settings that won't save, or all settings? If the latter, Alt.Binz can't find or write to the proper \misc directory.