Check your system performance to see if it's limited by the processor.
Check your system performance to see if it's limited by the processor.
Check if your system could face a performance limit with the CPU and board you have.
B450 has limited official PCIe4 support—some users can use it, but it’s constrained and may disappear with future BIOS updates. Its memory performance is also generally slower. The actual impact varies by use case. I wouldn’t recommend pairing a 5000x chip with B450 unless your motherboard already includes it.
The issue remains unresolved regarding inconsistent PCIe4 compatibility, and the B550 is just a few dollars more than the B450. No compelling reason to switch. My earlier view stays the same.
Others have mentioned that a motherboard isn't really a bottleneck in the usual way. But the B450 introduces artificial restrictions such as PCIe 3.0, even though the CPU supports PCIe 4.0. This could still matter. For instance, the 3050 and 6600/6600XT both have only 8 lanes, which might hurt performance if you insert them into a PCIe 3.0 slot instead of a PCIe 4.0 one. The 6500XT is even more restrictive, offering just 4 wired lanes, forcing you to use PCIe 3.0x4 on the GPU—something that isn't ideal. While the socket compatibility is good for those with older chipsets, it doesn’t mean you should upgrade to an older board. Opt for a B550 instead; it won’t cost much extra and will prevent limitations from outdated hardware.