PRO B850M-B GEN4
The MSI PRO B850M-B GEN4 is a Micro ATX AM5 motherboard on the B850 chipset. It supports DDR5 memory up to 8,200 MT/s and 2 M.2 slots. Full specs, power delivery, and current prices are below.
Prices update regularly and may differ at the retailer. This page contains affiliate links.
MaxMyBuild scores
How we score →How well the PRO B850M-B GEN4 is equipped for gaming and for productivity, scored 0–100 from its specs. Scores are fit-for-purpose: a capable board can top the gaming score without being the most expensive.
Weighs CPU power delivery, memory speed support, the GPU PCIe slot, Wi-Fi version, and M.2 storage — the things that actually matter for a gaming build.
Rewards fast, plentiful M.2 storage and USB I/O, PCIe expansion, memory capacity and slots — what matters for content creation and heavy multitasking.
CPU power
167 W
Limited · 0.7x
Wired for about 167 W, roughly 73% of the 230 W that the top Ryzen 9 chips pull. Pair it with a mid-range processor rather than a flagship. The figure comes from its 7+2+1 power-stage (VRM) layout and 8 EPS connectors. It is a rating of what the board is built to deliver, not a measurement, so treat it as headroom rather than a guarantee.
Specifications
Platform
- Chipset
- B850
- Socket
- AM5
- Form factor
- Micro ATX
Memory
- Type
- DDR5
- Slots
- 2
- Max speed
- 8,200 MT/s
- Max capacity
- 128 GB
- Channels
- 2-channel
- ECC / memory
- UDIMM
Power & VRM
- CPU power
- 167 W
- Phase config
- 7+2+1
- VRM stages
- 1H/1L
- EPS power
- 8
- VRM heatsink
- Partial (single bank)
Storage & Expansion
- M.2 slots
- 2
- M.2 layout
- 1× PCIe 5.0 ×4, 1× PCIe 4.0 ×4
- M.2 heatsinks
- Slots 1
- SATA ports
- 4 SATA3
- PCIe ×16 slots
- 1× PCIe 4.0 ×16
- Other PCIe slots
- 1× PCIe 3.0 ×1
Ethernet & Wi-Fi
- Realtek RTL8125
- 2.5 GbE
- Ethernet ports
- 1
- Wi-Fi
- None
USB & I/O
- Front USB-C
- 1× 10Gbps
Audio & Video
- Audio codec
- ALC897
- Audio jacks
- 3
- S/PDIF out
- Yes
- HDMI
- 1 port
- DisplayPort
- 1 port
- USB-C video
- None
Cooling, RGB & Design
- Fan headers
- 5
- 12V RGB headers
- 1
- 5V ARGB headers
- 3
Onboard & Diagnostics
- BIOS Flashback
- Yes (Rear)
- Diagnostics
- Debug LEDs
- Onboard buttons
- Clear CMOS
Compare the PRO B850M-B GEN4 against every other board on the motherboard comparison table. Not sure it fits your chip? The socket compatibility guide explains AM5 pairings.
Where to buy the PRO B850M-B GEN4
Every in-stock retailer offer we track, cheapest first.
| Retailer | Availability | Price | Buy |
|---|---|---|---|
| Newegg | In stock | $259.99 |  |
The PRO B850M-B GEN4 starts from $259.99 across 1 retailer (No onboard Wi-Fi). Prices update daily from live stock.
Which CPUs fit the PRO B850M-B GEN4?
Compare all CPUs →In-stock AM5 processors this board can run, socket-matched and within its 167 W power budget, ranked by gaming value (performance per dollar).
| Processor | Cores | Gaming | From | |
|---|---|---|---|---|
 | Ryzen 5 9600X AMD | 6/12 | 72.6 | $173.00 |
 | Ryzen 5 7600X AMD | 6/12 | 67.3 | $163.00 |
 | Ryzen 5 8500G AMD | 6/12 | 52.0 | $146.99 |
 | Ryzen 5 8400F AMD | 6/12 | 50.0 | $149.00 |
 | Ryzen 5 7500F AMD | 6/12 | 61.0 | $189.99 |
 | Ryzen 5 7600 AMD | 6/12 | 63.4 | $209.00 |
 | Ryzen 7 7700X AMD | 8/16 | 70.6 | $233.00 |
 | Ryzen 5 8600G AMD | 6/12 | 55.0 | $186.30 |
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