Why is my new PC lagging with PCIe 4.0 but fine on 3.0?
Asked by
TechieWizard92
I just built a new small form factor PC with an MSI B550i Gaming Edge motherboard, an R7 5700X processor, and a 4070 Ti Super graphics card, all of which support PCIe Gen 4.0. Even the riser cable I used is a 4.0 version that came with the ZS A4S case from ZSPC. However, I'm facing a frustrating issue where my PC becomes extremely laggy when running in PCIe x16 mode at 4.0. The moment I switch the settings in the BIOS to use PCIe 3.0—or remove the riser cable altogether—everything runs perfectly fine. It's really disappointing because I paid for PCIe 4.0 capabilities, and now I'm stuck using 3.0. I spent hours searching for a solution but couldn't find anything useful and I've seen others mention they're having similar problems. Any help would be greatly appreciated!
Answers
What version of the ZS A4S case did you get? V3 or v3.2? I suspect the riser cable might be the main issue, so clarifying that could help you troubleshoot.
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You might want to reach out to the case manufacturer about the riser cable. They might be able to send you a replacement. Sometimes these cables just don’t work right, especially if they’re not of the highest quality.
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Have you checked if the PCIe settings in your BIOS are set to 'Auto'? I had a similar lag issue with my MSI B650i Edge, and it worked better when I forced it to Gen 4 instead of leaving it on Auto. Might be worth trying!
TechieWizard92: Thanks for the tip! I did try setting it to 4.0, but unfortunately, it still didn’t work and I had to switch back to 3.0.
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There was a user here who faced a similar issue some time back, and it turned out to be related to the connectors on the riser. It might be worth checking those out, especially if you’re having these issues consistently.
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TechieWizard92: Good idea! I bought it from a Taobao seller that specializes in ITX cases, so getting a replacement could be a bit of a hassle. I’ll wait a few more days to see if others with similar setups report the same issue, then I’ll contact them if needed.