Vulcanberry

Thanks for the response - the m.2 slot uses chipset lanes, as does PCIe x16 slot 3. Only PCIe x16 slots 1 and 2 use CPU lanes from what I have been able to work out. I should also add that the problem also happens with just the PCIe extension card plugged in (i.e. without the drive actually installed in it).

The PC: PCPartPicker Part List CPU: Intel Core i7-6700K 4 GHz Quad-Core Processor Motherboard: Asus Z170 PRO GAMING ATX LGA1151 Motherboard Memory: G.Skill Ripjaws V 16 GB (2 x 8 GB) DDR4-2666 CL19 Memory Storage: Samsung 950 PRO 512 GB M.2-2280 NVME Solid State Drive Storage: Samsung 970 Evo Plus 1 TB M.2-2280 NVME Solid State Drive Storage: Seagate Barracuda 3 TB 3.5" 7200RPM Internal Hard Drive Video Card: MSI GeForce GTX 1080 Ti 11 GB DUKE 11G Video Card Optical Drive: LG WH14NS40 Blu-Ray/DVD/CD Writer Wireless Network Adapter: TP-Link Archer T9E PCIe x1 802.11a/b/g/n/ac Wi-Fi Adapter And also one of these: [PCIe NVMe expansion card] (https://www.orico.me/product/orico-m-2-nvme-to-pci-e-3-0-x4-expansion-card-psm2/) The Problem: This PC has been serving me well for a few years now, however I recently decided to upgrade by adding the second NVMe drive (the 970 EVO Plus). The original EVO 950 PRO was taking up the m.2 slot on the board, so I ordered the PCIe expansion card above. After installing the card into the 3rd PCIe 16x slot (board only has 1x and 16x slots) and powering up, there was no signal from GPU. After plugging the monitor cable over to the onboard GPU and restarting, I went into BIOS which showed no GPU installed in slot 1. The card was lighting up so was definitely still getting power. What I have tried so far After booting into windows, I initialised and formatted the new drive, and downloaded the latest motherboard firmware from the Asus website. I rebooted, installed the firmware, but the issue remained. I have tried various slot combinations (GPU in slot 2, PCIe extension in slot 2 or 1), playing around with BIOS settings, forcing PCIe to force gen3 but nothing has worked so far. I found the following PCIe lane diagram for the Z170 chipset which indicates that it should work if I plug the extension into slot 3 with the GPU in slot 1: It also indicates that I have plenty of PCIe lanes available (16 from CPU to cover GPU, 20 more from chipset to cover everything else. Other details Another thing I noticed, was the after booting back into windows I could not access the newly formatted drive. Disk management showed the drive as RAW and attempting to format it gave an instant error. I haven't been able to shed much light by reading the motherboard manual, and everything I have found online so far suggests that it should work. My suspicion at this point is that the 16x slots are configured to only take graphics cards - but I can't find anything to prove that or otherwise. I know this is older generation hardware but I am at my wits end after trying to figure this out all weekend! A link to the motherboard manual: from Asus website .