Build: Motherboard: ASUS ROG Strix Z390-I CPU: Core i5-9600k (Intel® UHD Graphics 630) Memory: Ballistix Sport LT 32GB Kit (16GBx2) DDR4 2400 MT/s (PC4-19200) DIMM 288-Pin BLS2K16G4D240FSC AIO: Cooler Master MasterLiquid LC120E RGB PS: EVGA 550 B3, 80+ Bronze 550W Case: Cooler Master RC-130-KKN1 Elite 130 - Mini-ITX Boot Storage: 1 Samsung EVO 250GB SSD Additional Storage: 2 Crucial P1 1TB 3D NAND NVMe PCIe M.2 SSD - CT1000P1SSD8 (2TB RAID 0 via software raid) 1 4TB Seagate Barracuda Mac OS 10.14.3 Issue: My issue is that my wired network will work fine and then immediately stall. For example, if I go to fast.com after rebooting my Mac, it will jump up to an OK 25Mbps. If I try to run the test again, it will go as high a few Kbps and then fail to complete altogether. Any test is the same—a download starts fast and then stalls, a Youtube video starts playing, then stalls. This stalling will continue until I restart the system altogether. Once I restart the system, it starts over the exact same. I've tried installing the IntelMausiEthernet.kext to the EFI partition as well as to the L/E path with the same result. This happens for both internet and local network activity. I've tried reinstalling, verifying that the IntelMausiEthernet kext is installed, verified that the correct hardware is present in the system report, and verified that the internet works without issue from the BIOS (downloaded firmware update without issue). I've went through the BIOS settings and disabled/enabled items based on the feedback through this mega-thread. I'm not really sure what to try next. Thanks in advance.