ASUS PRIME B850M-F — a straightforward AM5 micro-ATX board with PCIe 5.0 storage
AMD B850, Socket AM5PCIe 5.0 M.22 DDR5 slots, 128 GBmicro-ATX
The ASUS PRIME B850M-F is a micro-ATX motherboard for AMD Socket AM5 processors on the B850 chipset. It is the plain, sensible board in the range: two DDR5 slots taking up to 128 GB, a PCIe 5.0 M.2 socket for the boot drive and a second M.2 at PCIe 4.0, four SATA ports, a PCIe x16 slot for the graphics card, Gigabit Ethernet and BIOS FlashBack for updating the firmware without a processor fitted. What it does not have is wireless — and that is the single most important thing to know before ordering, because ASUS sells a near-identical board that does.
Compatibility — check before buying:
This is the non-WiFi version. It has no Wi-Fi and no Bluetooth, and no antenna is supplied. ASUS sells the PRIME B850M-F WIFI as a separate part number — the same board with a wireless module and antenna fitted — so if you need wireless, order that code instead or plan a PCIe or USB adapter. There is also no USB-C on the rear panel: the rear ports are two USB 5 Gbps Type-A, four USB 2.0 Type-A, HDMI, LAN, three audio jacks and the BIOS FlashBack button. The board has two DDR5 slots, not four, so 128 GB means two 64 GB modules, and it takes DDR5 only on Socket AM5 — AM4 processors and DDR4 do not fit. It is micro-ATX at 226 × 222 mm.
Best For
✓ Compact AM5 builds in micro-ATX cases
✓ Office and home systems on wired networking
✓ Budget-conscious Ryzen 9000 and 7000 builds
✓ Systems that will use a PCIe 5.0 NVMe boot drive
✓ Builders who prefer to add their own wireless card
✓ First builds — BIOS FlashBack makes updates forgiving
Key Features
PCIe 5.0 M.2 on a mainstream board
The primary M.2 socket runs at PCIe 5.0 x4 with Ryzen 9000 and 7000 series processors (PCIe 4.0 x4 with 8000 series), with a second M.2 at PCIe 4.0 x4 alongside it. Fast storage is one place this board does not economise.
DDR5 to 8200 MT/s and beyond with Ryzen 9000
Two DIMM slots supporting up to 128 GB of DDR5, with ASUS quoting 8200 MT/s and above under overclocking on Ryzen 9000 processors. Two slots rather than four is what makes a stable high memory clock easier to reach.
BIOS FlashBack on the rear panel
A dedicated button that updates the BIOS from a USB stick with no processor, memory or graphics card installed. On a new AM5 build with a very recent processor, that is the feature that turns a dead-on-arrival boot into a five-minute fix.
ASUS DIGI+ VRM and a full four SATA ports
Digital power delivery for the processor, and four SATA 6 Gb/s connectors alongside the two M.2 sockets — more SATA than several boards in this class still provide, which matters if you are carrying older drives across from an existing machine.
Technical Specifications
| Identification |
| Brand |
ASUS |
| Series |
PRIME |
| Model |
PRIME B850M-F |
| Part Number |
90MB1N90-M0EAY0 |
| EAN / GTIN |
4711636261296 |
| Platform |
| Socket |
AMD Socket AM5 |
| Chipset |
AMD B850 |
| Processor support |
AMD Ryzen 9000, 8000 and 7000 series desktop processors |
| Form factor |
micro-ATX, 226 × 222 mm |
| Memory & expansion |
| Memory type |
DDR5 |
| Memory slots |
2 DIMM |
| Maximum memory |
128 GB |
| Memory speed |
Up to 8200 MT/s and above under overclocking with Ryzen 9000 |
| PCIe slots |
1 × PCIe x16, 1 × PCIe x1 |
| Storage |
| M.2 socket 1 |
PCIe 5.0 x4 with Ryzen 9000 and 7000 series; PCIe 4.0 x4 with 8000 series |
| M.2 socket 2 |
PCIe 4.0 x4 |
| SATA |
4 × SATA 6 Gb/s |
| Connectivity & audio |
| Wired network |
Realtek 1 Gigabit Ethernet |
| Wireless |
None — no Wi-Fi and no Bluetooth on this model |
| Rear ports |
2 × USB 5 Gbps Type-A, 4 × USB 2.0 Type-A, 1 × HDMI, 1 × LAN, 3 audio jacks, BIOS FlashBack button |
| Rear USB-C |
None |
| Audio |
Realtek 7.1-channel HD audio codec |
| Power delivery |
ASUS DIGI+ VRM |
| In the box |
| Contents |
Motherboard, 2 × SATA cables, I/O shield, M.2 anchor package, quick start guide |
| Not included |
No Wi-Fi antenna — this model has no wireless module |
| Warranty |
| Warranty |
1-Year Warranty (Singular) |
| Manufacturer Term |
ASUS publishes a 3-year standard warranty for this motherboard on its support pages. Singular’s direct warranty is 1 year; beyond that we assist you with the manufacturer’s warranty process for its full duration. |
Frequently Asked Questions
Does this board have Wi-Fi?
No. The PRIME B850M-F has no wireless module and no Bluetooth, and no antenna is supplied. ASUS sells the PRIME B850M-F WIFI under a separate part number, which is the same board with Wi-Fi 6 and Bluetooth fitted. If you have already ordered this one and need wireless, a PCIe x1 or USB adapter is the straightforward fix — ask us and we will match one.
Can I fit 128 GB of memory?
Yes, but only as two 64 GB modules, because there are two DIMM slots rather than four. That also means you buy memory in the final configuration you want rather than adding a second pair later. On the plus side, two-slot boards generally reach higher stable memory clocks than four-slot ones.
Which M.2 socket should I use for my fastest drive?
The first one. It runs at PCIe 5.0 x4 with Ryzen 9000 and 7000 series processors, dropping to PCIe 4.0 x4 with the 8000 series. The second socket is PCIe 4.0 x4 regardless. Put a PCIe 5.0 drive in socket one and anything else in socket two.
Is there a USB-C port on the back?
No. The rear panel has two USB 5 Gbps Type-A ports, four USB 2.0 Type-A ports, HDMI, LAN, three audio jacks and the BIOS FlashBack button, with no Type-C among them. If USB-C on the rear matters to you, this is the wrong board and it is worth telling us so before you order.
Singular Expert Insight
The B850M-F is an honest budget board, and the two things it leaves out are the two things people notice: wireless, and a rear USB-C port. Neither is an accident — ASUS sells the WIFI version of exactly this board for people who need the first, and moving up a tier gets you the second. What it does not skimp on is storage: a genuine PCIe 5.0 M.2 socket plus a PCIe 4.0 one plus four SATA ports is more than the price suggests, and BIOS FlashBack makes a new AM5 build far less fragile. Two DIMM slots rather than four is worth planning around — buy the memory you want up front, in a matched pair, from our
memory section. See
graphics cards for the x16 slot. Tell us your processor and we will confirm BIOS support before you order.
Buyer’s Guide
Buy it if
You are building a compact, wired AM5 system and want a PCIe 5.0 M.2 socket without paying for features you will not use. BIOS FlashBack and four SATA ports make it an easy board to build on and to carry old drives into.
Skip it if
You need Wi-Fi or Bluetooth — the PRIME B850M-F WIFI is the same board with them fitted. Skip it too if you want a rear USB-C port, or if you were planning to start with two memory modules and add two more later.
Also consider
The ASUS PRIME B850M-F WIFI if you need wireless built in, or a full ATX B850 or X870 board if you want four memory slots, more M.2 sockets and rear USB-C.