ASUS Prime B550M-K

ASUS’s cheapest B550 board is the B550M-K, which is almost identical to the B550M-A, with just fewer parts. The biggest visual difference is that the B550M-K does not come with a power delivery heatsink, with a simple 4+2 power delivery design.

This does make the board look a lot cleaner with its straight lines, however this isn’t going to be a board for pushing the boundaries. It has only two fan headers around the socket, has a smaller chipset heatsink, and is missing some of the headers on the bottom of the board, such as the one for Thunderbolt or RGB. The latter might be a good thing.

Users will still have a USB 3.0 header, two USB 2.0 headers, four SATA ports, a full PCIe 4.0 x16 slot, a PCIe 4.0 x4 M.2 slot for fast storage, and a PCIe 3.0 x4 M.2 slot from the chipset. Audio is the same ALC887 codec with some PCB separation.

On the rear panel the user will get a combination PS/2 port, four USB 3.2 Gen 1 ports, an analog D-Sub video output, a DVI-D video output, a HDMI video output, two USB 3.2 Gen 2 Type-A ports, a gigabit Ethernet port (Realtek RTL8111H), and the audio jacks.

ASUS Prime B550M-A + Wi-Fi Biostar B550GTA
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  • althaz - Wednesday, June 17, 2020 - link

    Hmm, these seem mostly...pointless? More expensive than B450 by a lot, barely cheaper than the superior X570 boards (which have more PCIe lanes, more USB ports, etc)...these really need to be $50 cheaper across the (mother)board to make sense, IMO.
  • sing_electric - Thursday, June 18, 2020 - link

    It is interesting comparing similar X570 and B550 models within the same brand (or subbrand like Asus ROG or Gigabyte Aorus). It really seems like pricing is VERY close between them.

    Of course, if the VRMs are comparable, then for 90%+ of users, a X570 and a B550 are basically equivalent. In some cases it's almost like you're giving the user a choice between a newer B550 board with WiFi 6 and an older X570 board with AX but more USB ports or something, for within a few bucks of the same price (if you can find them at MSRP and in stock, which really has been an issue of late.)
  • jrbales@outlook.com - Wednesday, June 17, 2020 - link

    I was looking at the boards on morning of Jun 16th. Very few B550 boards in stock (not too unusual so soon to release) and prices were high, in the range there just a few months ago I could have bought an X570 board. However, X570s were mostly out of stock everywhere I looked, and those in stick were generally pushing $300 USD or more. I suspect either manufacturing has not completely ramped up after COVID-19 in Asia, or that there is still a shipping back-load via ocean freight bearing ships between Asia and North America. Maybe if we ever see a return to a semblance.
    nce of normal, prices might lower and parts return to stock,
  • romrunning - Wednesday, June 17, 2020 - link

    Shipping is main culprit here - big problem, including extra time spent in customs at ports (like LA in the US).
  • sing_electric - Thursday, June 18, 2020 - link

    Right - In February I picked up an X570 board for ~$30 under MSRP, so equivalent B550 board (same OEM, same 'line') would actually be a few bucks more... but adds a Thunderbolt header, WiFi 6 and 2.5 gig Ethernet (in exchange for PCIe lanes/slots and USB ports, and a 2nd m.2 connector). In the end, I think the X570 was a perfectly good choice on sale.
  • willis936 - Wednesday, June 17, 2020 - link

    I love that summary table. I wish it had an entry for “8 or more USB-A ports”. I actively use 15 on my desktop. The fewer PCIe cards and hubs needed, the better imo.
  • GNUminex_l_cowsay - Wednesday, June 17, 2020 - link

    Thanks for giving detailed and, hopefully, correct information about the PCIe configurations on these boards. Unfortunately many of the motherboard manufacturers don't give that information, make the information hard to find, give wrong information, or some combination of the above with regards to PCIe configuration.

    Out of curiosity, what happens when you put a pcie 3.0 x4 ssd in an x2 slot when the ssd's maximum read and write rates don't fully saturate x4? Is it just limited to the ~2GB/s bandwidth of the slot or does the ssd do something worse?
  • Lucky Stripes 99 - Wednesday, June 17, 2020 - link

    Yeah, it will transfer just a bit under 2 GB/s due to overhead. I had this same issue with my H97 board and my Samsung 970, so I opted to purchase a cheap M.2 PCIe 3.0x4 card. HD Tune showed an improvement, but not by much to notice much real world difference.
  • Allan_Hundeboll - Wednesday, June 17, 2020 - link

    What about the Gigabyte 550M s2h?
    It's 12$ cheaper than the ds3h, so I would like to know what gigabyte did to lower the cost.
  • xenol - Thursday, June 18, 2020 - link

    A complaint I had in previous AMD boards was how prevalent VGA ports were. I'm glad to see they're not so prevalent this time around.

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