Does AMD’s B550 support PCIe Gen 3.0 and Gen 4.0 at...

Hi, I have a B550 motherboard (GIGABYTE B550i) and GIGABYTE RX 5700 XT graphics card in a custom case with a 12-inch PCI-E riser cable.

The PCI-e riser cable is Gen 3.0 only, so I had to set the PCIe graphics to Gen 3.0 in the BIOS (to fix problems). My question is can I upgrade to a PCI-e 4.0 SSD (e.g. Samsung 980 Pro) and use the SSD on PCI-e Gen 4.0 while the graphics stay on Gen 3.0, or do I have to use the riser cable upgrade to PCI -e 4.0 too?

In other words, can the B550 chipset support graphics on PCI-e Gen 3.0 and an SSD on PCI-e Gen 4.0 at the same time? Many Thanks!

Hello pete,

Interesting problem anyway, so much so that I had to test your scenario myself! That said, my test system motherboard is a Crosshair VIII Hero with an X570 chipset, so I’m not sure you would see the same results on your B550i.

VIEW GALLERY – 2 IMAGES

Nevertheless, I can create my top x16 slot Gen3 on my x570 motherboard and let PCIe Gen 4.0 work with my Samsung 980 Pro on both m.2 slots without any problems. If you look at the motherboard specs, it seems like you have the front m.2 slot under the heat sink that supports PCIe 4.0 from the CPU. So this depends on your motherboard BIOS and the circuitry of the motherboard.

I can say that not all B550 motherboards have CPU lanes for the m.2, so your board is quite good. Another thing to note here is that the Samsung 980 Pro only loses 8-10MB / s in PCIe 3.0 mode 4KQ1 even if your setup doesn’t allow PCIe 4.0 on m.2 with the GPU on Gen3.