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Is it worth downgrading my BIOS to enable PCIe 4.0 on X470?

Level 7
Hi folks,

I've just replaced my old nvme drive and unfortunately I've found out that PCIe 4.0 support has been removed from the X470 BIOS at some point.

I'm using Ryzen 3900X, ASUS Crosshair VII Hero (x470) with the latest BIOS (4603) and Windows 11. My drive is a Corsair MP600 Pro XT, which should deliver around 7GB/s reads and writes, but unfortunately it does only half that, same as my old PCIe 3.0 nvme drive.

Going through ASUS BIOS release notes, I found out they stripped support for PCIe 4.0 after BIOS 2606. Obviously there were a lot of bug fixes since then, but I've never had an issue with my system so far.

Should I downgrade the BIOS from 4603 to 2606 (or earlier?) to re-gain PCIe 4.0 support, or is not worth it? These are second gen PCIe 4.0 drives and I expect they would perform much better with full bandwidth, but I could be wrong. Perhaps the performance is the same and difference is only seen in benchmarks.

Any advice would be appreciated 🙂


Level 7

I have the same mobo CH7 Hero (without Wifi for me) and CPU (R9 3900X too) with the last bios 5302 now.

In my case, I prefer to keep my systemù updated to the lastest version , nor the 2606, because you lose the Resizable BAR if go chose to have the 2606 bios.

And as I have a RX6600XT with only 8GB VRAM, I prefer to have this option activated for games.

I have a NVME PCI-e 4 capable (WD BLACK SN850) but I have no problem with the GEN 3 mode, which is rapid to boot to win10 too.

If 2606 had Resizable BAR inside (that is not...) I should stay in 2606.... 😋.

If a moded bios should be done by a geek-guy. I GIVE MY MONEY NOW ! (it should update the mobo like A CROSSHAIR VIII HERO