Running Win 10 ARM on M1 MBA.. randomly (maybe once every day or two), I created a website alight motion apps the upload speed slows to a crawl in VM for my website. No issue with the download speed. 80 down/~0.15 up speedtest. 80/80 in Mac. Using shared network. Not sure if this is a Windows 10 or Parallels NIC driver issue. The fix is simply to disable and reenable the NIC (in Windows). Haven't tried iPerf or anything to confirm it's both LAN and WAN, but would I assume so? Kind of hard to definitively pin down when it happens, but it SEEMS to occur after Windows or the Mac has slept. Event viewer shows repeated errors below until it's fixed, maybe Netbios-related. I will try to disable Netbios but does anyone has any ideas?
i agree this reply. Fix 1: Disable Peer-to-Peer Update Fix 2: Adjust the Internet Bandwidth Settings Bigwoice Fix 3: Update your WiFi drivers Fix 4: Repair system files Fix 5: Disable Windows Auto-Tuning