AMD Confirms PCIe 4.0 Not Coming to Older Motherboards (X470, X370, B350, A320)

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One of the salient points of the next generation Ryzen 3000 CPUs coming next month was the support around PCIe 4.0. As the successor to PCIe 3.0, offering double the bandwidth and a range of other optimizations, the combination of the new technology paired with existing and new AM4 motherboards was always going to generate a bit of an issue with support. AMD, through a Reddit post, and confirmed by our sources at AMD’s partners, has clarified the issue.

Moving from PCIe 3.0 to PCIe 4.0 on a motherboard isn’t overly difficult. In order to qualify for PCIe 4.0 use, the signaling guidelines for the connecting traces between the CPU and PCIe slots have to be met. If the PCIe 3.0 motherboard was over-engineered in the first place, and supports PCIe 3.0 very well, there is every chance that those same connecting traces can carry a PCIe 4.0 signal without any issue. The problem becomes when some motherboards can succeed in PCIe 4.0, whereas others cannot because they can only barely support PCIe 3.0.

Before the launch of Ryzen 3000, many users (ourselves included) had speculated about PCIe 4.0 support on older motherboards, such as X470, X370, and the cheaper chipset variations. For those users who had bought into this market with a nice expensive motherboard, it was expected that these models were designed rigorously enough to also support PCIe 4.0. We have even seen some GIGABYTE motherboards already provide the option in the BIOS to support PCIe 4.0. However, AMD has nixed that idea, and those BIOS options will be reversed.

The only motherboards that will support PCIe 4.0 in the future will be the 500-series chipset, which is currently only the X570 range, although the B550 line-up is expected to come later this year. These chipsets are qualified for PCIe 4.0, but older chipsets will not be. AMD doesn’t want to create confusion in the market based on motherboard quality, where some users might be able to have it and others might not.

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