I just bought a 5070 Ti and noticed it's operating at 8x in the Nvidia Control Panel. My motherboard is the ASUS Strix B450-f Gaming, and I know it's because both of my M.2 slots are filled. It says that if the second M.2 slot is in use, PCIe x16 slot 1 drops to 8x. I'm looking for a workaround since upgrading my motherboard isn't an option right now. If I get an affordable PCIe x16 to NVMe adapter, will that solve the problem? I don't see any restrictions mentioned for the lower x16 slots, so I think it might even improve SSD speeds. I just want to make sure I'm not overlooking any issues and that running the 5070 Ti on PCIe 3.0 x8 won't severely impact its performance.
6 Answers
The second PCIe x16 slot actually shares lanes with your top PCIe slot. You might want to try the third slot instead. It’ll run at PCIe 2.0 x4, which is still pretty fast for gaming. Just be aware of that bandwidth sharing.
I’d simply replace your second M.2 drive with a SATA SSD. That could free up some lanes and simplify the setup.
Honestly, I wouldn’t stress too much about it. Once you upgrade your platform later, this bottleneck will likely disappear, and you probably aren’t losing significant performance right now anyway.
That option will probably make performance worse. The reason you're at 8x is that the CPU lanes are shared with the second M.2 slot. The lower x16 might even be disabled if it’s sharing lanes with another device. I’d recommend considering a larger M.2 drive for the first slot instead.
Using an adapter won't resolve the fundamental issue of PCIe lane limitations. Everything is sharing bandwidth among the ports. The difference in performance between 8x and 16x for the GPU might be minor, but running benchmarks like 3DMark could help you see where you stand compared to similar systems. If you notice a significant drop, consider swapping one of the NVMe drives for a SATA SSD or consolidating your SSDs into a larger single drive.
Nah, Asus motherboards really struggle with this configuration. I dove deep into this issue myself, so feel free to check out my earlier posts for more insights.
I didn't see that in the manual. It only mentions that the PCIe x16_3 shares with PCIe x1_2 and x1_3. So I’m not clear on the lane sharing beyond that.