Upgrade guide: MSI MPG B550 Gaming Plus
Updated Oct. 20, 2026 · Written from this device's verified specifications
The MSI MPG B550 Gaming Plus is a desktop motherboard with nothing soldered down — the memory, drives and processor are all socketed, so you can upgrade any of them. Here's what fits, the limits of each upgrade path, and a safe general outline for doing the work.
At a glance
- 4 DDR4 DIMM slots, up to 128 GB total
- 2 M.2 slots plus 6 SATA 6 Gb/s ports
- Socket AM4 for Ryzen 3000, 4000 G-Series, 5000 and 5000 G-Series desktop CPUs
| 4x DDR4 DIMM (288-pin), 128 GB max | 4 × DDR4 DIMM · up to 128 GB total · 4400 MT/s |
|---|---|
| 2x M.2 (PCIe/SATA) + 6x SATA 6 Gb/s | 2 × SSD M.2 2242 / M.2 2260 / M.2 2280 / M.2 22110 (NVMe / SATA) |
| Socket AM4 (replaceable CPU) | AM4 · Ryzen 3000, Ryzen 5000, Ryzen 5000, Ryzen 5000 · max 105 W |
Lifecycle and support
A current model: sold new and supported.
| Milestone | Date |
|---|---|
| Release First available to buy. |
June 16, 2020
Estimate
Stated as the global launch date of the whole MSI B550 lineup, including the MPG B550 GAMING PLUS. Japanese market availability began later (2020-07-10 per kakaku.com). Source ↗ |
Dates not listed haven't been published by the manufacturer or a reliable third party.
RAM upgrade
There are 4 DDR4 DIMM slots (288-pin, desktop DIMMs — not laptop SO-DIMMs). The board takes un-buffered memory only; registered server modules are not supported. The maximum is 32 GB per module and 128 GB in total across all four slots.
The board runs dual-channel memory, and slot order matters. Put your first module in DIMMA2 (the second slot from the CPU). For two sticks, A2 plus B2 is the correct dual-channel pair. For the best stability, modules should match in type, number and density, and MSI recommends matched kits — don't combine two separate 'kit of 2' packages.
Speed depends heavily on how many sticks you install and whether they are single- or dual-rank. The headline 4400 MT/s is achievable only with one single-rank stick. With four dual-rank sticks the validated top speed is 3600 MT/s (other combinations fall in between: one dual-rank stick per channel tops out around 3866 MT/s, two single-rank sticks per channel around 4000 MT/s).
Memory will often boot at a lower frequency than its rated speed. To get the speed on the box, enable A-XMP in the BIOS or set the DRAM frequency manually. MSI advises keeping DIMM voltage at or below 1.35 V to protect the CPU, and suggests extra RAM cooling if you use four modules or overclock.
ECC UDIMMs will physically install, but this board runs them in non-ECC mode, so you get no error correction — don't buy ECC memory for the feature. There is no memory card slot on this board.
Buying tip: buy one matched kit at the capacity and speed you want, and be realistic about speed if you're filling all four slots.
Buying tips
- DDR4 desktop DIMMs (288-pin), un-buffered only — not SO-DIMM, not registered
- Aim for 2 sticks first: A2 + B2 gives you dual-channel with the best chance of high speeds
- Budget for a matched kit; mixing kits of different speed, timings or voltage isn't recommended
Storage upgrade
You get two M.2 slots and six SATA 6 Gb/s ports for 2.5-inch or 3.5-inch drives. As a bare motherboard there are no drive bays or thickness limits — how many drives physically fit is up to your case. MSI publishes no per-port capacity limit, so the ceiling is set by the drives and their firmware rather than the board.
M2_1 is fed by the CPU and is the flexible slot: it accepts NVMe or SATA M.2 drives in lengths 2242, 2260, 2280 and 22110. M2_2 is chipset-fed and NVMe-only (no SATA M.2 drives) and takes lengths up to 2280.
Two things to plan around. First, an NVMe drive in M2_2 disables PCI_E3, the lower x16-length expansion slot — so if you use a capture card or network card in that slot, put your NVMe drive in M2_1 instead. Second, PCIe 4.0 speeds on M2_1 (and on the main graphics slot) only happen with a Ryzen 3000 or 5000 non-G processor; with a G-Series APU or other supported chip those slots run at PCIe 3.0.
For redundancy, the board supports RAID 0/1/10 on SATA and RAID 0/1 on M.2 NVMe drives.
Buying tip: for a fast boot drive, pick an NVMe M.2 2280 drive and use M2_1 — it's the slot with the widest support and the best chance of PCIe 4.0 speeds.
Buying tips
- Check the length label on the drive (2280 is the safe common size; only M2_1 takes 22110)
- M2_2 is NVMe-only — a SATA M.2 drive will not work there
- Count your expansion cards before filling M2_2, since it switches off PCI_E3
CPU upgrade
The processor sits in a Socket AM4 and is replaceable. MSI's current support list covers Ryzen 3000, Ryzen 4000 G-Series, Ryzen 5000 and Ryzen 5000 G-Series desktop processors.
Two caveats before you buy. The Ryzen 3 3200G and Ryzen 5 3400G are AM4 chips but will not boot in this board, so don't pick them up cheaply expecting them to work. And if your board is older stock, it may need a BIOS update before it will recognise a Ryzen 5000 series CPU — check the board's BIOS version first, and note that updating may require a currently supported processor installed.
Power: MSI doesn't publish an explicit maximum TDP on its spec sheet. Its CPU support list includes 105 W parts (such as the Ryzen 9 5950X, 5900X and 3900X), so 105 W is effectively supported. The board has a single 8-pin +12V EPS connector, which limits how far you can push a 105 W chip with heavy overclocking.
A new CPU can also affect your storage and graphics speeds — remember that PCIe 4.0 on M2_1 and the main x16 slot needs a Ryzen 3000/5000 non-G processor. Note also that the secondary x16-length slot is electrically x4 and the board supports CrossFire only, not SLI.
Buying tip: choose from the current support list for your BIOS version, and prefer a non-G Ryzen if you want PCIe 4.0 for your SSD or graphics card.
Buying tips
- Ryzen 3000 / 4000 G-Series / 5000 / 5000 G-Series desktop CPUs only — no 3200G or 3400G
- Check whether your board needs a BIOS update before it will run a Ryzen 5000 chip
- 105 W is the practical limit; heavy overclocking is constrained by the single 8-pin EPS connector
How to upgrade
Before you start
- Back up anything important before you touch the hardware.
- Shut down the computer, switch the PSU off and unplug the power cable.
- Ground yourself — discharge static on the case or use an anti-static strap before handling parts.
- Open the case. For exact disassembly and screw locations, follow your case and board documentation — MSI's manual covers the board itself.
- Install the new part: seat modules in the slots described above, fit M.2 drives in the correct slot for their length and interface, or replace the CPU in Socket AM4. AMD/MSI documents describe the board's slot layout and population order; follow the owner's manual for the exact installation and any retention hardware.
- Close the case, reconnect the power and start the machine.
- Check that the BIOS/firmware sees the new part. For RAM, confirm the capacity and enable A-XMP or set the DRAM frequency if the modules are running below their rated speed. For storage, confirm the drive appears and note whether installing it has disabled PCI_E3. For a CPU, update the BIOS first if needed, then verify the model is recognised.
Steps
- Back up your data
Save anything important before opening the case. - Power off and unplug
Shut the system down, switch the PSU off and unplug the mains cable. - Ground yourself
Discharge static by touching the metal chassis or wearing an anti-static strap. - Open the case
Remove the side panel. Consult MSI's owner's manual for the board's slot layout and any device-specific fasteners. - Install the part
RAM: fill DIMMA2 first, then B2, then A1 and B1. Storage: match the drive's length and interface to the M.2 slot, or connect a SATA drive to one of the six SATA 6 Gb/s ports. CPU: update the BIOS first if the board predates support for your processor, then replace the chip in Socket AM4. - Close up and check the BIOS
Reconnect power, boot, and confirm the BIOS sees the new hardware — and enable A-XMP if your RAM is running below its rated speed.
Good to know
- The 105 W figure is inferred from MSI's CPU support list — MSI does not state a maximum TDP on its specification page.
- MSI's older manual describes CPU support more narrowly ('3rd Gen and future with BIOS update'); its current product page lists 3000, 4000 G-Series, 5000 and 5000 G-Series and supersedes it.
Frequently asked questions
How much RAM can the MSI B550 Gaming Plus take?
Up to 128 GB in total, using four DDR4 DIMMs of up to 32 GB each. It's un-buffered desktop memory only; registered server modules won't work.
Which RAM slots should I use?
Start with DIMMA2 (second slot from the CPU), then B2. That A2 + B2 pair gives you proper dual-channel. Fill A1 and B1 only after those.
Does it support ECC memory?
ECC UDIMMs will install, but the board runs them in non-ECC mode, so you get no error correction. There's no point buying ECC modules for this board.
Does it support PCIe 4.0 SSDs?
Yes, in M2_1 — but only if you have a Ryzen 3000 or 5000 non-G processor. With a G-Series APU or another supported chip, the slot runs at PCIe 3.0 instead.
Which CPUs fit the MSI B550 Gaming Plus?
Socket AM4 Ryzen 3000, 4000 G-Series, 5000 and 5000 G-Series desktop processors. The Ryzen 3 3200G and Ryzen 5 3400G are AM4 but will not boot in this board. Older stock may need a BIOS update for Ryzen 5000.
Will an M.2 drive disable anything?
An NVMe drive in the second M.2 slot (M2_2) switches off PCI_E3, the lower x16-length expansion slot. The first slot, M2_1, has no such trade-off.
Official documents and references
- MSI MPG B550 GAMING PLUS — official specifications
Slot counts, capacities, supported CPUs and RAID support. - PDF MSI MPG B550 GAMING PLUS — user guide (English, PDF)
Slot layout, DIMM population order, memory speed table and power connectors. - PDF MSI MPG B550 GAMING PLUS — manual (PDF)
Installation details and memory configuration guidance. - Kingston memory compatibility search — MSI MPG B550 GAMING PLUS
Validated module sizes and matched-kit advice.