My setup: Z390 Aorus Pro, i9-9900k, 32GB (2x16GB). Board has 2x256GB NVMe SSDs in it, a dual Realtek NIC in x1_1 slot, GPU in x16_1 and a (currently empty) m.2 expansion card in the bottom x16_3 (x4) slot. 2x2tb hdds, 1tb ssd on SATA ports. keyboard, mouse, headset, xbox 360 controller adapter on USB. Win10 Pro x64. Prior to this, the only actual problem I've had was when first setting up the system, where it would claim I didn't have enough USB resources available and my headset wouldn't work. Once system drivers were installed and updated this stopped and it seemed fine, although once the desktop loads I would hear the "USB device connected" noise. I wanted to add two more ethernet ports to the system (I'm partly using this for some learning/work, and I wanted to give 4 VMs dedicated NICs on isolated networks) so I ordered two Dell 0FCGN Broadcom 5720 x1 slot dual NICs (one for this system, one for another). Installing either Broadcom card in the available x1 slot (x1_3) would cause the system to only recognize a single DIMM: the DIMM in slot B1 would show up as only 128MB, and slot A1 would report correct size. Slots B2 and A2 would not function at all. Thinking I had a failed DIMM I tried swapping them around (it's a 4x16GB kit, half in this system and half in another) but every DIMM that went into slot B1 reported 128MB, then showed 16GB when put in slot A1. With all four slots occupied (or memory in just A2/B2) the system wouldn't POST at all, it would get stuck in a loop where the display never initialized. I tried rearranging the cards (putting just the Broadcom card in x1_1 with nothing else; moving the Realtek card to x1_3 and putting Broadcom in x1_1, even put the Broadcom card in x16_3, the bottom x4 slot), and no combination would work. Maybe it was a PCIe lane thing, so I put an x1 wifi card in x1_3, with the Realtek in x1_1, and... no issues with the memory. All seemed fine. So right now I've got two Broadcom NICs, neither of which work in any combination in this system. OK, maybe they're both bad, I can test them in my other box when I get it reassembled. But it's also a Gigabyte Z390 board so I'm not expecting any different behavior. Except... now, when I boot into Windows, I've got some odd behavior. It takes about 20 seconds to log in after I type my password. About 30 seconds before desktop icons appear. Nearly two minutes after that before the taskbar starts responding (keyboard works fine, but I can't click the start menu). Event logs are full of error 10010 and a few 10016. I get a 7000 error for bitlocker. I'm chasing these errors down the rabbit hole, but... they aren't in any of the logs until this. Thing is, I never actually made it into Windows when these Broadcom cards were installed. The OS didn't even start booting, I just kept going into the BIOS to troubleshoot. Maybe a Windows reset will help fix it but I can't pinpoint anything that would have caused the OS (which never attempted boot when the problem cards were installed) to have issues. I haven't exactly been thrilled with the board (lack of RGB management in BIOS, the aforementioned USB resource error message, now whatever this is) and I'm starting to think maybe I should just try a different board, or just sell the whole setup and sit on my hands until Ryzen 3 lands. Have any of you seen something like this?