PCIe 4.0 feature pops up in X470 Motherboard BIOS

by Hilbert Hagedoorn on: 05/20/2019 07:40 AM | source: tomshardware | 31 comment(s)

The motherboard manufacturers are hard at work prepping X570 series motherboards for the new Ryzen 3000 processors. These will also bring PCI-Express 4.0 towards the eco-system. Interesting, Gigabyte released new BIOS updates for Ryzen 3000 compatibility to their (among others) X470 motherboards. And guess what the BIOS is showing?

IT seems that the company has added the option for PCIe 4.0 in the most recent bios update for its X470 Aorus Gaming Wi-Fi motherboard. This information was spotted by an observant Reddit user and then got verified by Tom's Hardware. Gigabyte has not yet made an official announcement about the new option.

It might be a crossover feature intended for X570 which propagated somehow towards X470. In an update from AMD they write:

300- and 400-series AM4 motherboards can support PCIe 4.0. AMD will not lock the out feature, instead it will be up to motherboard vendors to validate and qualify the faster standard on its motherboards on a case-by-case basis. Motherboard vendors that do support the feature will enable it through BIOS updates, but those updates will come at the discretion of the vendor. As mentioned below, support could be limited to slots based upon board, switch, and mux layouts.


PCIe Version	Line Code	Transfer Rate	x1 Bandwidth	x4	x8	x16
1.0	8b/10b	2.5 GT/s	250 MB/s	1 GB/s	2 GB/s	4 GB/s
2.0	8b/10b	5 GT/s	500 MB/s	2 GB/s	4 GB/s	8 GB/s
3.0	128b/130b	8 GT/s	984.6 MB/s	3.938 GB/s	7.877 GB/s	15.754 GB/s
4.0	128b/130b	16 GT/s	1.969 GB/s	7.877 GB/s	15.754 GB/s	31.508 GB/s

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Astyanax
Senior Member

Posts: 9566
Joined: 2018-03-21

#5670989 Posted on: 05/20/2019 07:49 AM

Some of the existing boards are built well enough to handle Gen 4 from the CPU controller.

Update: We spoke with AMD representatives, who confirmed that 300- and 400-series AM4 motherboards can support PCIe 4.0. AMD will not lock the out feature, instead it will be up to motherboard vendors to validate and qualify the faster standard on its motherboards on a case-by-case basis. Motherboard vendors that do support the feature will enable it through BIOS updates, but those updates will come at the discretion of the vendor. As mentioned below, support could be limited to slots based upon board, switch, and mux layouts.

Our sources tell us that after unlocking the feature via a BIOS update, the older motherboards supply a PCIe 4.0 x16 connection to the first slot on the motherboard, but the remainder of the slots revert to PCIe 3.0 signaling rates. That's because any trace routing on the motherboard that exceeds six inches requires newer redrivers and retimers that support PCIe 4.0's faster signaling rates. That means the PCIe slot nearest to the CPU will easily support PCIe 4.0, while the other slots, including M.2 ports, will run at a PCIe 3.0 signaling rate.

https://www.tomshardware.com/news/amd-ryzen-pcie-4.0-motherboard,38401.html

fantaskarsef
Senior Member