Does the B450 Tomahawk support Ryzen 5000?

Many boards gained support through later BIOS updates, but not all revisions did. Check the board's BIOS version and MSI's CPU support list before buying for a Ryzen 5000 chip.

Can I use PCIe 4.0 graphics cards and SSDs on it?

The board is PCIe 3.0 only, so a PCIe 4.0 card or SSD will run at PCIe 3.0 speeds. That costs some peak SSD bandwidth but works fine for most graphics cards.

How many M.2 drives can I install?

One. The single M.2 slot takes 2242, 2260 and 2280 drives. For more fast storage you would add SATA SSDs to the six SATA ports.

Does it have Wi-Fi or Bluetooth?

No. Networking is a single gigabit Ethernet port, so you need a USB or PCIe Wi-Fi card for wireless.

What memory does it take?

Four DDR4 DIMM slots, dual-channel. MSI lists supported speeds per CPU, and higher kits may run below their rated speed depending on the memory controller.

Is CrossFire worth using on this board?

It supports a second AMD card, but the second slot runs at reduced bandwidth and most games no longer benefit from dual GPUs. Treat it as a legacy feature.