Prime B450M-K II
The ASUS Prime B450M-K II is a Micro ATX AM4 motherboard on the B450 chipset. It supports DDR4 memory up to 4,400 MT/s and 1 M.2 slot. 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 Prime B450M-K II 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
115 W
The Prime B450M-K II is wired to feed about 115 W to the processor. The figure comes from its 4+2 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
- B450
- Socket
- AM4
- Form factor
- Micro ATX
Memory
- Type
- DDR4
- Slots
- 2
- Max speed
- 4,400 MT/s
- Max capacity
- 64 GB
- Channels
- 2-channel
- ECC / memory
- UDIMM
Power & VRM
- CPU power
- 115 W
- Phase config
- 4+2
- VRM stages
- 1H/2L
- EPS power
- 8
Storage & Expansion
- M.2 slots
- 1
- M.2 layout
- 1× PCIe 3.0 ×4
- SATA ports
- 4 SATA3
- PCIe ×16 slots
- 1× PCIe 3.0 ×16
- Other PCIe slots
- 2× PCIe 2.0 ×1
Ethernet & Wi-Fi
- Realtek RTL8111H
- 1 GbE
- Ethernet ports
- 1
- Wi-Fi
- None
USB & I/O
- Rear USB-A
- 2× USB 2.0, 4× 5 Gbps
- Front USB 3 headers
- 1
- Front USB 2 headers
- 2
Audio & Video
- Audio codec
- Realtek
- Audio jacks
- 3
- HDMI
- 1 port
- DisplayPort
- None
- USB-C video
- None
Cooling, RGB & Design
- Fan headers
- 2
- 12V RGB headers
- 0
- 5V ARGB headers
- 0
- PCB colour
- Black
- Heatsink colour
- Gray
Onboard & Diagnostics
- BIOS Flashback
- Yes (rear)
- TPM header
- Yes
Compare the Prime B450M-K II against every other board on the motherboard comparison table. Not sure it fits your chip? The socket compatibility guide explains AM4 pairings.
Where to buy the Prime B450M-K II
Every in-stock retailer offer we track, cheapest first.
| Retailer | Availability | Price | Buy |
|---|---|---|---|
| Newegg | In stock | $88.27 |  |
| Amazon | In stock | $172.00 |  |
The Prime B450M-K II starts from $88.27 across 2 retailers (No onboard Wi-Fi). Prices update daily from live stock.
Which CPUs fit the Prime B450M-K II?
Compare all CPUs →In-stock AM4 processors this board can run, socket-matched and within its 115 W power budget, ranked by gaming value (performance per dollar).
| Processor | Cores | Gaming | From | |
|---|---|---|---|---|
| Ryzen 5 5500 AMD | 6/12 | 38.7 | $84.93 | |
| Ryzen 5 5600 AMD | 6/12 | 52.0 | $140.99 | |
| Ryzen 3 4100 AMD | 4/8 | 30.5 | $91.65 | |
| Ryzen 5 4500 AMD | 6/12 | 33.5 | $104.99 | |
| Ryzen 5 5600X AMD | 6/12 | 53.7 | $171.92 | |
| Ryzen 7 5700 AMD | 8/16 | 52.0 | $172.99 | |
| Ryzen 5 5600XT AMD | 6/12 | 53.7 | $189.99 | |
| Ryzen 7 5700X AMD | 8/16 | 55.3 | $209.00 |
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