I'm on a MacBook Pro with High Sierra, and a Parallels instance running a clean Windows 10 Pro instance of whatever the latest update is. The host OS is consistently getting ~70 Mbps up/down, which is the limit of my router. The Windows guest is lucky to get 1.5 Mbps. This has been true since the initial install of the guest OS; nothing has changed recently. The only forum and help topics I've found are related to bridged networking and they all suggest using shared networking; I am and have been using shared networking. Where can I start troubleshooting this issue?