Next up is the Asus Prime B550M-K. As above, we’ll list the specifications first, then cover the board in more detail below the table.
Specifications - Asus Prime B550M-K
| Socket | AM4 |
|---|---|
| Chipset | B550 |
| Form Factor | MicroATX |
| Voltage Regulator | 6-Phase (4+2) |
| Video Ports | (1) D-Sub, (1) DVI-D, (1) HDMI (v2.1) |
| USB Ports | (4) USB 3.2 Gen 2, Type-A (10 Gbps), (2) USB 3.2 Gen 1, Type-A (5 Gbps) |
| Network Jacks | (1) 1 GbE |
| Audio Jacks | (3) Analog |
| Legacy Ports/Jacks | PS/2 |
| Other Ports/Jack | ✗ |
| PCIe x16 | (1) v4.0 (x16) |
| PCIe x8 | ✗ |
| PCIe x4 | ✗ |
| PCIe x1 | (2) v3.0 (x1) |
| CrossFire/SLI | ✗ |
| DIMM slots | (4) Supports up to DDR4 4600(OC) |
| M.2 slots | (1) PCIe 4.0 x4 / SATA + PCIe (up to 110mm) |
| U.2 Ports | ✗ |
| SATA Ports | (4) SATA3 6 Gbps (RAID0, 1 and 10) |
| USB Headers | (1) USB v3.2 Gen 1, (2) USB 2.0 |
| Fan/Pump Headers | (3) 4-Pin (Supports PWM and DC) |
| RGB Headers | ✗ |
| Legacy Interfaces | ✗ |
| Other Interfaces | FP-Audio, COM, TPM |
| Diagnostics Panel | ✗ |
| Internal Button/Switch | ✗ |
| SATA Controllers | ✗ |
| Ethernet Controllers | Realtek TRL8111H (1 GbE) |
| Wi-Fi / Bluetooth | ✗ |
| USB Controllers | ✗ |
| HD Audio Codec | Realtek ALC887 |
| DDL/DTS Connect | ✗ / ✗ |
| Warranty | 3 Years |
Just as the other budget boards we’ve looked at don’t include a lot of accessories, the Asus Prime B550M-K follows suit. You’ll get what you need, but little more. Below is a list of all of the accessories included with the board.
- User's manual
- I/O shield
- (2) SATA cables
- Driver DVD
- M.2 SSD screw package
At first glance, the Asus motherboard has a busy appearance even without a shroud or VRM heatsink in sight. The glossy black PCB gives way to white lines shooting through the board from the audio and IO area up through the VRM, socket, and DIMM slots. Between that and all of the exposed bits, there’s a lot going on. The good news is that black and white will work with most build themes.
On the RGB front, our miniature Asus doesn’t have integrated LEDs or RGB headers. If you want this motherboard and need some in your build, you will have to buy some that do not depend on a motherboard for power and control.
Taking a look at the top half of the board, we’re able to plainly see all of the board’s unmentionables (power delivery), since there isn’t a heatsink on the VRMs. Power is fed to the CPU through a single 8-pin EPS connector. Just to the right of the AM4 socket is one (of three) 4-pin fan headers. Each header is able to control PWM and DC fans. The manual doesn’t detail the output for these headers so we’ll assume they are 1A/12W.
There are four single-side locking DIMM slots, two black and two grey, supporting up to 128GB of DDR4 RAM and speeds listed to DDR4 4600 with 3rd Gen Ryzen desktop CPUs (APUs show support to DDR4 4800). On the right edge is the 24-pin ATX for board/slot power and a front-panel USB 3.2 Gen1 header. Just above the top M.2 slot in the middle of the board is the chassis fan header.
Power delivery on this board is managed by an Asus DigiPlus chip, which is an ASP1106G 4+2 channel controller in disguise. Power for Vcore is sent to a Vishay SiRA14DP (58A) on the high side and SiRA12 (25A) on the low side. Again, this isn’t the most robust we’ve seen by far, but it is similar to the other ATX boards we're looking at here. In fact, during our stock stress test, we saw a couple of instances of throttling with our Ryzen 9 3900X. And things were even worse at 4.3 GHz where it throttled constantly. This board simply didn’t handle the 3900X under these stress test conditions. However, gaming and other shorter benchmarks showed no sign of performance limitations, as we’ll see later.
Moving on to the bottom half, on the left side and fully exposed is the Realtek ALC887 codec along with the small yellow Japanese audio capacitors. The audio codec hails from Realtek’s budget range, but it should be sufficient. If you’re an audiophile, none of these boards are going to be up to snuff when paired with a high-end set of headphones or speakers. But for casual use, you’ll be fine.
In the middle of the board is a single full-length PCIe 4.0 x16 slot, along with two PCIe 3.0 x1 slots. The full-length slot gets its lanes/bandwidth from the CPU while the small slots are fed from the chipset. Due to the slot configuration, you’ll lose access to the top slot using any video card that is over single slot width (which is most of them).
On both sides of the primary GPU slot are two M.2 sockets, neither of which come with a heatsink. The top slot supports modules up to 110mm in length as well as both SATA and PCIe 4.0 x4 devices (fed from the CPU). The bottom socket is fed from the chipset and runs at PCIe 3.0 x4 speeds (and also supports PCIe and SATA modes). Just below the pushpin-attached chipset fan heatsink are the four vertically oriented SATA3 ports (supporting RAID0, 1 and 10). You will not need to share connectivity (SATA ports) with any M.2 configuration.
Across the bottom edge are several headers with various functionality. You’ll find the front panel headers, USB and more. Below is a complete list of headers and ports on the bottom edge.
- Front panel audio
- COM header
- 4-pin Chassis fan header
- Front panel header
- Speaker header
The rear IO on the budget-minded Asus Prime B550M-K is fairly sparse, but still has everything needed for the basics including video outputs, USB ports, ethernet and audio. On the video side, if you’re using an APU and its integrated video you’ll have a choice of D-SUB, DVI-D, or HDMI (v2.1) outputs. On the USB side of things, there are a total of six ports, four USB 3.2 Gen1 and two USB 3.2 Gen 2. Six ports may be a bit anemic for some, though there are headers on the board for additional ports for the front panel. The audio stack consists of three analog plugs (a SPDIF header is on the motherboard) and the 1 GbE Ethernet port. Last but not least, there’s a PS/2 port for legacy keyboard and mouse functionality.
Software
Asus’ main utility, AI Suite 3, includes several applications with various functions covering fan control, overclocking, and more. Asus also provides a program to update various drivers and applications, called EZ Update. We’ve captured a few screenshots of AI Suite and other applications including the Armory Crate. The biggest difference here is the Prime boards will be black and light blue versus the red found on the ROG boards.
ALBM u-(ais,armrcrt)
Firmware
To give you a sense of the Firmware, we’ve gathered screenshots showing a majority of the BIOS screens.
Asus’ BIOS is one of my personal favorites, as it’s easy to find what you are looking for and typically things aren’t buried several levels down. The BIOS options are plentiful, especially for overclocking, and there are controls for just about anything you can think of. Like the software, the firmware theme is also skinned differently as compared to pricier boards, in this case running black and a lighter blue as opposed to the ROG theme of black and red.
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