Can I use the same CPU in both boards?

No. The Z790 uses Intel LGA1700 and the B550 uses AMD AM4. A CPU fits one or the other, never both.

Which is better for a new gaming build?

The Z790 ELITE AX, because it supports current Intel CPUs, DDR5 and PCIe 5.0. The B550 only makes sense if you already own an AM4 chip.

Can I put DDR4 in the Z790?

No. The Z790 ELITE AX is DDR5 only. The B550 AORUS ELITE uses DDR4.

Is the B550 still worth buying?

Only for a budget build reusing an AM4 CPU and DDR4 memory. AM4 gets no new CPUs, so there is no upgrade path.

Does the Z790 have Wi-Fi?

Yes. The AX suffix means built-in Wi-Fi 6E. The B550 AORUS ELITE listing shows Ethernet only.

Which board has more PCIe 5.0?

The Z790 ELITE AX. It has a PCIe 5.0 x16 slot plus PCIe 4.0 and 3.0. The B550 tops out at PCIe 4.0.

Gigabyte AORUS Z790 Elite AX vs Gigabyte B550 AORUS Elite

These are not interchangeable. The Z790 ELITE AX takes Intel 12th–14th gen CPUs and DDR5, while the B550 AORUS ELITE takes AMD Ryzen AM4 chips and DDR4. Buy the Z790 if you are building a new Intel DDR5 system; buy the B550 if you already own an AM4 CPU and DDR4 memory. The Z790 is $189.99 at Best Buy as of November 7, 2026; the B550 has no price listed here, so check its current price before deciding.

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