MSI B450 TOMAHAWK MAX upgrade guide: RAM, storage and CPU

Lifecycle and support

A current model: sold new and supported.

Dates not listed haven't been published by the manufacturer or a reliable third party.

RAM upgrade

The board has four DDR4 DIMM slots, and all memory is socketed — nothing is soldered. It takes standard 288-pin desktop DIMMs; laptop SO-DOMMs won't fit. The current spec page puts the ceiling at 128 GB total, which means 32 GB in each of the four slots. Note that MSI's older Quick Start guide says 64 GB and 3466 MT/s; the current spec page supersedes it, and the older figures just reflect the BIOS of that time. Reaching 128 GB needs a BIOS based on ComboPI 1.0.0.3 or newer — with an older BIOS you'll be capped at 64 GB.

Speed depends on your CPU as much as the board. 4133 MT/s (via A-XMP) is listed only with Ryzen 3000 R5/R7/R9 processors; with other CPUs the top is 3466 MT/s. Standard JEDEC speeds run 1866 to 2667 MT/s, and XMP kits typically need 1.35 V instead of the standard 1.2 V. In practice, filling all four slots or using dual-rank modules usually lowers the speed you can actually reach, so 3200-3606 MT/s... 3200-3600 MT/s is a sensible target.

ECC is half-supported: ECC UDIMMs fit but run in non-ECC mode, so don't buy them expecting error correction. Registered or server memory (RDIMM/LRDIMM) will not work at all. And for best performance, install memory in matched pairs — the board runs dual channel, and pairs keep it there.

Buying tips: buy a matched kit (2x or 4x modules from the same package) rather than mixing sticks; check MSI's QVL for the exact kit you're considering; and if you want 128 GB, plan on a BIOS update first.

Buying tips

• Buy matched pairs or a 4-stick kit so dual-channel mode works as intended.
• Check MSI's memory QVL for your kit, especially above 3200 MT/s.
• Buy plain DDR4 desktop UDIMMs — not SO-DIMMs, not registered server memory.

Storage upgrade

There's one M.2 slot and six SATA 6 Gb/s ports, so you can add a fast SSD and still keep plenty of hard drive or SATA SSD space. The M.2 slot is a Key M slot that accepts 2242, 2260, 2280 or 22110 length drives, and it works with either NVMe or SATA M.2 SSDs. It's wired for PCIe 3.0 x4 with 1st, 2nd or 3rd Gen Ryzen and Ryzen/Vega APUs (x2 with Athlon/Vega), so a Gen 4 or Gen 5 NVMe drive will work but will run at Gen 3 speed — there's no PCIe 4.0 here even with a Zen 2 CPU.

Two limits to keep in mind. First, an M.2 SATA drive disables the SATA5 and SATA6 ports, so you lose two of your six SATA connectors; an NVMe drive doesn't. Second, there is only one M.2 slot, and adding a second NVMe drive via an adapter card is a poor option: the second long PCIe slot (PCI_E4) is only PCIe 2.0 x4 electrically, and it drops to x2 if any of the PCIe 2.0 x1 slots is populated.

There's no official per-drive capacity limit, and 4 TB NVMe drives are listed as compatible by memory vendors, so multi-terabyte drives should be fine. RAID 0, 1 and 10 are available for SATA drives only — there's no NVMe RAID. How many 2.5-inch or 3.5-inch drives you can physically mount depends on your PC case, not the motherboard.

Buying tips: if you want maximum speed from a single drive, choose an NVMe M.2 SSD so you keep all six SATA ports. Gen 4 drives cost more for speed you won't see here, so a good Gen 3 drive is the sensible pick. Make sure the drive length matches one of the four supported M.2 sizes (2242, 2260, 2280 or 22110).

Buying tips

• Pick an NVMe M.2 SSD if you want to keep all six SATA ports.
• Gen 3 NVMe drives are the sweet spot — Gen 4/5 drives run at Gen 3 speed anyway.
• Check your case for drive bays and mounting space before buying big hard drives.

CPU upgrade

The processor sits in a socketed AM4 socket, so it's fully replaceable. Officially supported are 1st, 2nd and 3rd Gen AMD Ryzen (including Ryzen with Radeon Vega Graphics and 2nd Gen Ryzen with Radeon Graphics) and Athlon with Radeon Vega Graphics desktop processors. Ryzen 5000 support is a special case: the MAX's larger BIOS chip apparently allowed it through later BIOS updates, but MSI's own documents here don't cover it, so check MSI's official CPU support list for this exact board before buying a Ryzen 5000 chip.

MSI publishes no official TDP ceiling for this board. Its VRM handled a 65 W Ryzen 7 3700X comfortably in testing, and 65-105 W AM4 parts are fine as long as your case moves some air over the VRM heatsink. The big 12- and 16-core 105 W parts will run the VRM warm under sustained all-core loads, so good case airflow matters more if you go that route.

Buying tips: check MSI's CPU support list for the exact chip and the BIOS version it needs — you may have to update the BIOS before the new CPU will boot. If you're jumping generations (say, Ryzen 1000 to Ryzen 3000), that BIOS-first step usually applies. And pair a new CPU with a decent cooler if you're moving to a 105 W part.

Buying tips

• Verify the exact CPU on MSI's support list for the B450 TOMAHAWK MAX before ordering.
• Update the BIOS with your current CPU installed if the new chip needs a newer version.
• For 105 W 12/16-core chips, make sure your case airflow reaches the VRM heatsink.

How to upgrade

Before you start

• Back up anything important before you open the case.
• Shut down, switch the PSU off and unplug the power cable.
• Ground yourself (touch the bare metal case or use an anti-static strap) before handling components.
• Open the case and install the part. For latches, screws and mounting details, follow the owner's manual for your exact case and board.
• Close the case, reconnect power and boot.
• Enter the BIOS and confirm it sees the new part (total memory, the drive, or the new CPU), and update the BIOS first if the component requires it.

Good to know

• The B450 TOMAHAWK MAX and the plain B450 TOMAHAWK are different boards — don't swap BIOS files or spec sheets between them.
• Where MSI's Quick Start guide and the current spec page disagree on RAM (64 GB / 3466 MT/s vs 128 GB / 4133 MT/s), trust the current spec page; the older document predates 32 GB DIMM support.
• Ryzen 5000 support is not confirmed in MSI's own documents listed here — verify on MSI's CPU support list first.

Frequently asked questions

How much RAM can the MSI B450 TOMAHAWK MAX take?

128 GB total, using four 32 GB DDR4 DIMMs, but only with a BIOS based on ComboPI 1.0.0.3 or newer. With an older BIOS you're limited to 64 GB. MSI's older Quick Start guide says 64 GB; the current spec page supersedes it.

Does the MSI B450 TOMAHAWK MAX support Ryzen 5000?

Not according to MSI's own documents listed here, which name 1st to 3rd Gen Ryzen, Vega APUs and Athlon Vega. Ryzen 5000 support is reported to have arrived through later BIOS updates thanks to the MAX's larger BIOS chip, but this isn't documented in the sources we've seen — check MSI's official CPU support list for this board before buying.

Does it support PCIe 4.0 SSDs?

A Gen 4 (or Gen 5) NVMe drive will physically work in the M.2 slot, but the slot is PCIe 3.0 only, so the drive runs at Gen 3 speed. There's no PCIe 4.0 on this board even with a Zen 2 CPU.

Can I use ECC memory?

ECC UDIMMs fit and the board will run them, but in non-ECC mode — you get no error correction. Registered or server memory (RDIMM/LRDIMM) doesn't work at all.

How many SSDs can I add?

One M.2 SSD (NVMe or SATA) plus six SATA 6 Gb/s drives. If the M.2 drive is a SATA type, it disables the SATA5 and SATA6 ports, leaving you four. An NVMe M.2 drive leaves all six SATA ports free. The number of physical drive bays depends on your PC case.

Will a faster RAM kit actually run at its rated speed?

Only if your CPU allows it: 4133 MT/s is listed for Ryzen 3000 R5/R7/R9, while other CPUs top out at 3466 MT/s. Filling all four slots or using dual-rank modules usually reduces the achievable speed, so 3200-3600 MT/s is the realistic sweet spot. Enable A-XMP in the BIOS and check MSI's QVL for your kit.

Official documents and references

• MSI B450 TOMAHAWK MAX — official specification page
  Current specs: 128 GB / 4133 MT/s RAM, M.2 and SATA details, expansion slots.
• PDF MSI B450 TOMAHAWK MAX — product datasheet (PDF)
  Supported CPU generations, memory and storage features.
• PDF MSI B450 TOMAHAWK MAX — Quick Start guide (PDF)
  SATA port layout and M.2/SATA sharing. Its RAM figures (64 GB, 3466 MT/s) are older than the current spec page.
• Kingston — memory search for MSI B450 TOMAHAWK MAX
  Compatible module listings and 32 GB module support.
• Memorycow — MSI B450 TOMAHAWK MAX memory and storage compatibility
  Module voltages, capacity options and multi-terabyte NVMe listings.