Costs up to $250 for X570 – Tailored Application Scenario
Costs up to $250 for X570 – Tailored Application Scenario
Hey everyone, I'm considering an upgrade and thinking about getting an X570 Aorus Pro with a 5900X. The question is: Can I run two NVMe drives while keeping the x16 bandwidth on the GPU slot? I’m not worried about the expensive boards with three NVMe slots. Right now I’m using a 5700XT, so having it at x8 speeds isn’t an issue, but I’m also planning to upgrade the GPU later—maybe to a 6900XT soon. Any thoughts would be great! Thanks!
Typical motherboards feature a first M.2 port with four PCIe lanes right at the CPU, and a second M.2 port if equipped—those with PCIe lanes are sourced from the chipset. The CPU provides 24 lanes: 4 for the chipset, 4 for the M.2 slot, and 16 for the graphics card. The chipset generates eight PCIe lanes and allocates them according to the manufacturer’s needs—generally four go to the second M.2 port, one or three to the x1 slots, and so forth. On certain boards, the bottom PCIe x16 port (physically x4 but electrically x1) can be swapped out for x1 or x2 ports, or even turned off entirely when you install an NVMe SSD in the second M.2 slot, since the lane routing changes. For optimal performance, consider B550 boards if you’re okay with a second M.2 only supporting PCIe 3.0 (up to ~3.9 GB/s). B550 models were released later and often include improved VRM setups, enhanced cooling, and newer audio chips like ALC1200 or ALC1220, plus 2.5 Gbps Ethernet. Think of these as upgrades that add value without breaking the budget. You sacrifice only PCIe 4.0 lanes in the chipset area—typically just the bottom x16 slot, a few x1 slots, and possibly fewer USB 10G ports.
In short, fitting two NVMe drives without affecting the PCIe lane for your GPU seems impossible without upgrading to HEDT. That’s disappointing because even a modest performance drop in a 2080Ti could become noticeable with a much faster GPU like a 3090.
Your understanding is correct—PCIe bandwidth shouldn't significantly affect GPU performance.
The f... how did you reach that idea the PCI-E X16 is not working? I meant something different. The CPU provides 24 PCI-E lanes. Four always connect to chipset, four always go to the first M.2 slot—16 usually goes to the PCI-E X16 port (video card)—it depends on the motherboard maker if it can split them into two PCI-E 4.0 x8 slots. This allows both an NVMe M.2 slot and a video card to operate at maximum speed. The chipset functions like a network switch, offering one outgoing connection (to CPU) and several ports (for PCI-E lanes, devices inside, SATA controllers, USB controllers, etc.). It generates 8 PCI-E lanes that can be directed to a PCI-E slot, M.2 connectors, or internal components. Most motherboard makers will allocate four of those lanes from the eight created by the chipset and send them to a second M.2 slot. So, typically you’ll have full PCI-E X16 for the video card, full PCI-E 4.0 x4 for the first M.2 connector, and full PCI-E 4.0 (or 3.0 on B550) on the second M.2 slot using chipset lanes.
In most games, a PCIe 3.0 x8 connection suffices. You might experience a slight delay in frame rates compared to PCIe x16. Upgrading to PCIe 4.0 provides roughly double the data transfer speed, making a PCIe 4.0 x8 essentially the same as PCIe 3.0 x16 in terms of bandwidth. It wouldn't be a major issue if a motherboard dedicates those 16 PCIe lanes to graphics cards and splits them between two slots or reserves some for other functions. In fact, the Gigabyte B550 Aorus Master does this: https://www.gigabyte.com/Motherboard/B55...-rev-10#kf It features three M.2 ports, all compatible with PCIe 4.0 x4. The first M.2 slot connects straight to the CPU's four lanes, while the other two draw from the PCIe x16 slot for graphics cards. If those M.2 slots lack NVMe SSDs, the graphics card operates at PCIe 4.0 x16 speed fully. Adding one or two NVMe SSDs into the lower two slots can switch the graphics port to PCIe 4.0 x8. If a single SSD only supports PCIe 3.0, the graphics slot may revert to PCIe 3.0 x8.
There are 24 lanes total. Four always connect to the chipset for onboard devices, leaving 20 lanes. Sixteen go to the GPU and four to the first NVMe. The extra four lanes likely come from restricting the GPU slot to an x8 configuration. PCI-e slots don't support x12, so you can't simply take only four lanes from that slot.