MSI B450M-A PRO 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 takes desktop DDR4 memory in two 288-pin DIMM slots. These are full-size UDIMMs, not laptop SO-DIMMs, and there is no soldered memory to work around. Both slots are usable, and if you want dual-channel performance you need two matched modules rather than one large stick.

The ceiling is 32 GB per module and 64 GB in total, but 32 GB modules only work on a BIOS built on ComboPI 1.0.0.3 or newer, so update the BIOS before you fit them. Not every source agrees on this number: MSI's current spec page and Kingston's compatibility list both confirm 64 GB with two 32 GB sticks, while some datasheets and retailer listings still say 32 GB. Those older figures reflect the board's launch specification, when 16 GB was the largest common module.

Speed is very CPU-dependent. The standard (JEDEC) profiles are 1866, 2133, 2400 and 2667. With A-XMP switched on, MSI quotes up to 4133 MT/s — but only with Ryzen 3rd Gen R5/R7/R9 processors. Other CPUs top out lower, around 3466 or 3200 MT/s, and first-generation Ryzen memory controllers often cannot reach 3200 and above at all. Older datasheets quote 3200 MT/s as the maximum, so treat the highest figure as a best-case result rather than a guarantee. Also expect modules to run below their rated speed at default settings; the board does not automatically apply an XMP profile for you.

Two more things to keep in mind. ECC UDIMMs physically fit, but the board runs them in non-ECC mode, so you get no error correction — do not buy this board expecting true ECC. Registered or buffered memory is not supported at all. And MSI advises keeping DIMM voltage below 1.35 V to avoid stressing the CPU's memory controller. When installing, populate DIMMB1 first, exactly as the manual describes.

Buying tips: choose a two-stick DDR4 UDIMM kit in the capacity you want, skip ECC and registered modules, and only pay for high-speed memory if you already run a Ryzen 3rd Gen R5/R7/R9. Remember that available capacity is always slightly less than installed capacity.

Buying tips

• Buy two matched DDR4 UDIMM sticks for dual channel, not one large module
• Only buy 32 GB modules if your BIOS is ComboPI 1.0.0.3 or newer
• Ignore high speed ratings unless you have a Ryzen 3rd Gen R5/R7/R9
• Don't pay extra for ECC — it runs without error correction here

Storage upgrade

There is one M.2 Key M slot on the board, and it accepts both NVMe (PCIe) and SATA SSDs. Drive lengths 2242, 2280 and 22110 all fit, and Kingston's list confirms that double-sided 22110 modules are fine. The common 2280 format is the easiest to shop for.

How fast that slot runs depends on your processor. With 1st, 2nd and 3rd Gen Ryzen CPUs and Ryzen with Vega Graphics it is PCIe 3.0 x4. With Athlon with Vega Graphics, A-series and Athlon X4 parts it drops to PCIe 3.0 x2, which is worth knowing if you are eyeing a fast NVMe drive on an older APU.

Alongside the M.2 slot you get four SATA 6 Gb/s ports, with RAID 0, 1 and 10 available. One caveat: installing an M.2 SATA drive is likely to disable one of those four ports. MSI's spec page does not spell out the port sharing, so check the storage chapter of the manual before you commit — and if you want to keep all four SATA ports free, choose an NVMe drive instead.

The motherboard itself has no drive bays. How many 2.5-inch or 3.5-inch drives your PC can hold, and how thick they can be, depends entirely on your case. There is no stated capacity ceiling on the board; large SATA drives and current NVMe drives are limited only by what is available to buy.

Buying tips: prefer an NVMe M.2 SSD in 2280 form, check your case's drive bays before buying a 3.5-inch hard disk, and remember that an M.2 SATA drive costs you one of your four SATA ports.

Buying tips

• Prefer an NVMe drive so all four SATA ports stay available
• 2280 is the standard length; 2242 and 22110 also fit
• Check your case's bays and thickness limits before buying 2.5-inch or 3.5-inch drives

CPU upgrade

The processor sits in Socket AM4 (PGA, 1331 pins) and is fully replaceable. Officially supported are 1st, 2nd and 3rd Gen AMD Ryzen, Ryzen with Radeon Vega Graphics, 2nd Gen Ryzen with Radeon Graphics, Athlon with Radeon Vega Graphics, A-series and Athlon X4 processors — in other words Zen, Zen+ and Zen 2 chips plus older Excavator-based parts.

Ryzen 5000 (Vermeer and Cezanne) is a grey area. It is not in the printed specification, but MSI's B450 MAX boards have a 32 MB BIOS and received BIOS and AGESA updates that add Ryzen 5000 support. Before buying, check MSI's CPU compatibility list for your exact processor and the BIOS version it needs. Ryzen 7000 and Ryzen 9000 are not supported at all — they use a different socket.

On power: MSI publishes no TDP limit for this board. Its CPU list includes both 65 W and 105 W parts, so 105 W chips will boot and run. However, the power delivery on this budget model is basic, with small, unheatsinked power stages, so 65 W processors are the sensible ceiling. A 105 W chip will work but tends to run hot and throttle under sustained load.

Buying tips: stick to 65 W Ryzen processors, favour a 3rd Gen part for the best memory support, and only buy a Ryzen 5000 chip after confirming it on MSI's CPU list and updating the BIOS. Skip anything from the Ryzen 7000 or 9000 series.

Buying tips

• Choose a 65 W Ryzen processor — the board's power circuitry is basic
• Verify your exact chip on MSI's CPU compatibility list before ordering
• Update the BIOS first if you are going to a Ryzen 5000 processor

How to upgrade

Before you start

• If you are also adding a heavy graphics card, note that the manual warns it may need a support bracket.

Steps

1. Back up your data
   Save anything important before you open the case, especially if you are replacing a drive.
2. Power off and unplug
   Shut the PC down fully and unplug the mains lead so nothing is live while you work.
3. Ground yourself
   Discharge static by touching bare metal on the case, and avoid working on a carpeted floor.
4. Open the case
   Follow the owner's manual for the exact disassembly steps for your PC.
5. Fit the new part
   For RAM, populate DIMMB1 first, then the second slot. For storage and the CPU, seat the part as the manual shows. If you are using 32 GB memory modules or a Ryzen 5000 processor, make sure the BIOS is updated first.
6. Close the case
   Replace the side panel and reconnect the power.
7. Check the BIOS
   Start the PC and confirm the BIOS sees the new memory, drive or processor, and that the memory is running at the speed you expect.

Good to know

• Sources disagree on the maximum RAM: MSI's current spec page and Kingston say 64 GB total, while some datasheets and retailer listings say 32 GB. The higher figure requires a newer BIOS.
• Sources also disagree on maximum memory speed: MSI lists 4133 MT/s via A-XMP, while older datasheets say 3200 MT/s. The top speed applies only to Ryzen 3rd Gen R5/R7/R9 processors.
• MSI's spec page does not state whether an M.2 SATA drive disables a SATA port; this is commonly the case on MSI B450 boards, so confirm in the manual.

Frequently asked questions

How much RAM can the MSI B450M-A PRO MAX take?

Up to 64 GB in total, using two 32 GB DDR4 UDIMMs. You need a BIOS with ComboPI 1.0.0.3 or newer for 32 GB modules. Some older datasheets still say 32 GB, which was the launch spec before large modules became common.

What RAM speed does the MSI B450M-A PRO MAX support?

Standard profiles run from 1866 up to 2667. With A-XMP, MSI quotes up to 4133 MT/s, but only with Ryzen 3rd Gen R5/R7/R9 processors; other CPUs top out at around 3466 or 3200 MT/s. Memory speed depends on the CPU, so very fast modules may not reach their rated speed.

Does the MSI B450M-A PRO MAX support ECC memory?

ECC UDIMMs fit and work, but the board runs them in non-ECC mode, so there is no error correction. Registered or buffered memory is not supported.

Does the MSI B450M-A PRO MAX have an M.2 slot for NVMe SSDs?

Yes, one M.2 Key M slot that takes NVMe or SATA drives in 2242, 2280 and 22110 lengths. With a Ryzen CPU it runs at PCIe 3.0 x4; with Athlon and A-series parts it drops to PCIe 3.0 x2.

Will an M.2 SATA SSD disable a SATA port?

Probably yes — on MSI B450 boards an M.2 SATA drive usually disables one of the four SATA ports. MSI's spec page does not confirm this for this model, so check the storage section of the manual, or simply choose an NVMe drive and keep all four ports.

Does the MSI B450M-A PRO MAX support Ryzen 5000 processors?

Not out of the box, but as a MAX board it received BIOS and AGESA updates that add Ryzen 5000 (Vermeer and Cezanne) support. Check MSI's CPU compatibility list for your exact chip and the required BIOS version before buying. Ryzen 7000 and Ryzen 9000 are not supported.

Official documents and references

• MSI B450M-A PRO MAX official specification page
  Official specs for memory, storage and CPU support.
• PDF MSI user guide for the A320M-A PRO MAX and B450M-A PRO MAX
  Official manual, shared with the A320M-A PRO MAX; covers this board's installation details.
• Kingston memory compatibility list for the MSI B450M-A PRO MAX
  Confirms 64 GB with two 32 GB modules and double-sided 22110 M.2 drives.
• PDF MSI B450M-A PRO MAX datasheet (PDF)
  Useful as a source of the older 32 GB / 3200 MT/s launch figures.