SN770 NVMe M.2 supports PCIe Gen4x2 instead of four lanes.
SN770 NVMe M.2 supports PCIe Gen4x2 instead of four lanes.
Hey there, I'm trying to figure this out because it's getting frustrating. I have a WD_Black SN770 1TB SSD and an Asus B550F motherboard. The board claims it supports Gen4x4 on slot 1 and Gen3x4 on slot 2. However, slot 1 only shows Gen4x2, while the other slot works as expected with Gen3x4. I've done a few things: moved the GPU to the second PCIe 16x slot, rearranged all SATA drives to slots 1 and 2, reinstalled Windows, checked the BIOS for lane settings, forced Gen4 via BIOS, and even reset the drive multiple times. Still nothing. The SSD's official site says it supports Gen4x4, but the speeds I got were only 3.7GB/s instead of the expected 5.1GB/s. What could be going wrong?
You analyzed the manual and confirmed the specifications. You're wondering whether placing the drive in M.2_2 supports full 3.0 x4 performance or only 3.0 x2, which could indicate an issue. You're also considering other x4 PCIe drives for M.2_1 to test compatibility.
I installed it in M.2_2 and it worked at Gen3x4. Since I don’t have any other M.2 drives available, I think I’ll go to RMA or request a refund. I was expecting to use it with DirectStorage games when they came out (which is why I chose the 1TB model), but it looks like I’ll need to switch back to SATA SSD for now.
This might point to a hardware problem rather than an NVMe issue. It seems the connection isn’t establishing properly. I’d try swapping in a simple x4 NVMe card and see if it works with four lanes. If not, you could install one externally and use a fast USB port for portable storage or backup.
It might not be necessary for generation version 4. Version 3 could work just fine if all four lanes function properly. I believe there’s nothing in your adjustments that’s causing the issue.