Gigabyte's latest BIOS update enables PCIe 4.0 support on its AMD X470 and B450 motherboards

PCIe Gen4 in the Gigabyte X470 Aorus Gaming Wi-Fi 7 motherboard. (Source: u/mVran on Reddit)
PCIe Gen4 in the Gigabyte X470 Aorus Gaming Wi-Fi 7 motherboard. (Source: u/mVran on Reddit)
Gigabyte has released new AGESA microcode updates for its X470 and B450 offerings that seem to enable PCIe Gen4 support in the BIOS. The feature, originally thought to be available only on upcoming AMD X570 motherboards, can enable Gen4 speeds on the nearest PCIe slot connected to the Ryzen 3000 CPU. Other PCIe lanes going to the chipset and M.2 slots will continue to operate at PCIe Gen3 speeds.

We know that AMD's upcoming Zen2 Ryzen 3000 CPUs will bring support for the new PCI Express (PCIe) 4.0 standard but so far, it was thought that this would also require a motherboard with the X570 chipset. Looks like that might not be entirely true as Gigabyte has rolled out BIOS updates to its X470 and B450 motherboards that enables the PCIe 4.0 option in the BIOS. 

Spotted by user mVran on Reddit for the Gigabyte X470 Aorus Gaming Wi-Fi 7 motherboard, the latest F40 BIOS update adds a Gen4 option to the PCIe Slot Configuration setting in the BIOS. Users with Gigabyte B450 motherboards in the same thread have also reported that the PCIe Gen4 option along with an unlocked BCLK was available upon installing the F40 update.

While the prospect of PCIe 4.0 support for older motherboards sounds enticing, there are a few things to keep in mind here. For one, this setting will work only when a Ryzen 3000-series CPU is installed in the socket. Also, the PCIe 4.0 speeds are applicable only for lanes directly coming from the CPU — in most cases, this is the first x16 slot. The lanes coming from the chipset and M.2 slots will continue to work at PCIe 3.0 speeds. 

AMD had earlier confirmed that current 300 and 400-series AM4 motherboards can support PCIe 4.0 but has left it to the motherboard vendors' discretion whether or not to implement the feature. The slot selection for Gen4 support will also depend on the board's layout and PCIe lane lengths. Any PCIe slots with PCIe 3.0 switches or extra routing will not be able to support Gen4 speeds.

The fact that users of older Ryzen motherboards stand a chance to get at least one PCIe slot upgraded to Gen4 is a quite a bonus for customers. Most motherboard OEMs have started shipping BIOS updates to offer in-place support for Ryzen 3000 chips. It remains to be seen which of these updates actually enable PCIe Gen4 support and on which motherboard models.

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> Notebook / Laptop Reviews and News > News > News Archive > Newsarchive 2019 05 > Gigabyte's latest BIOS update enables PCIe 4.0 support on its AMD X470 and B450 motherboards
Vaidyanathan Subramaniam, 2019-05-19 (Update: 2019-05-19)
Vaidyanathan Subramaniam
I am a cell and molecular biologist and computers have been an integral part of my life ever since I laid my hands on my first PC which was based on an Intel Celeron 266 MHz processor, 16 MB RAM and a modest 2 GB hard disk. Since then, I’ve seen my passion for technology evolve with the times. From traditional floppy based storage and running DOS commands for every other task, to the connected cloud and shared social experiences we take for granted today, I consider myself fortunate to have witnessed a sea change in the technology landscape. I honestly feel that the best is yet to come, when things like AI and cloud computing mature further. When I am not out finding the next big cure for cancer, I read and write about a lot of technology related stuff or go about ripping and re-assembling PCs and laptops.