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AM5 & PROM21 chipset: Technical data revealed  

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AMD not too long ago introduced its AM5 motherboards at Computex 2022, however we’d be mendacity if we mentioned we didn’t see it coming. There have been many leaks on the web relating to AMD’s AM5 motherboards that appear to have given us extra data round AM5 than AMD has divulged themselves. We hope you take pleasure in our AM5 & PROM21 chipset article.

The web site Angstronomics has introduced us some juicy data round AM5 and delved deeper into the technical side of AMD’s new chipset configuration. 

AMD’s AM5 platform chipset was devised from the begin to be designed and manufactured by a third-party provider. This differs from the earlier socket era (AM4) as AMD repurposed their consumer I/O die chiplet to be used because the chipset. Repurposing this die resulted in a high-cost excessive energy chipset that was able to PCIe Gen 4 hyperlink speeds, however it required lively cooling by a really noisy cooling fan – one thing X570 customers nonetheless complain about at the moment. 

Now, AMD has introduced their PCIe Gen 5 prepared chipset named Promontory 21, or ‘PROM21’ for brief, will likely be equipped and manufactured by ASMedia. The plan was to have MediaTek in on manufacturing in addition to ASMedia, however MediaTek has but to fabricate a single chiplet for AMD. 

The AMD PROM21 chipsets for AM5 are available three configurations. 

  • Low-end A620, with a single defeatured PROM21
  • Mid-range B650, with a single PROM21
  • Excessive-end X670, with twin PROM21 chipsets on the motherboard

The low-end A-class chipset configuration will launch later than the B650 and X670 boards when the lower-tier APUs launch.

The high-end X670 chipset is exclusive, that includes 2 PROM21 chipsets linked in a daisy-chained configuration. The primary chipset connects to the CPU as regular, after which the second chipset connects to the primary chipset.

Listed below are the specs of a single PROM21 chipset (B650):

  • 19 x 19 mm FCBGA package deal
  • Most Energy ~7W
  • One PCIe 4.0 x4 Uplink to host
  • Two PCIe 4.0 x4 downlink controllers (Complete 8 Lanes)
  • 4 PCIe 3.0 x1 / SATAIII 6 Gbps versatile ports (4L PCIe or 2L PCIe + 2x SATA or 4x SATA)
  • Six USB 3.2 Gen 2 10 Gbps ports (Two of the ports may be fused to type one USB 3.2 Gen 2×2 20Gbps port, with 4 remaining 10Gbps USB ports)
  • As much as 6 extra USB 2.0 ports

For the A-class chipset, one PCIe 4.0 x4 downlink is disabled.

For a typical motherboard with 4x SATA ports, the B650 variant can help one PCIe 4.0 x4 M.2 NVMe SSD, whereas the A-class chipset doesn’t help any. The remaining PCIe 4.0 lanes are used for WiFi, Ethernet, and PCIe x1 growth slots.

The X670 boards have their daisy-chained chipsets linked with PCIe 4.0 x4. 

The specs of a twin PROM21 daisy-chained board (X670) are as follows:

  • Two 19 x 19 mm FCBGA packages
  • Most Energy ~7W x 2
  • One PCIe 4.0 x4 Uplink to host
  • Three PCIe 4.0 x4 downlink controllers (Complete 12 Lanes)
  • Eight PCIe 3.0 x1 / SATAIII 6 Gbps versatile ports (4L PCIe + 4x SATA or 2L PCIe + 6x SATA)
  • 12 USB 3.2 Gen 2 10 Gbps ports (4 of the ports may be fused to type Two USB 3.2 Gen 2×2 20Gbps ports, with eight remaining 10Gbps USB ports)
  • As much as 12 extra USB 2.0 ports

The WiFi and a pair of.5G Ethernet may be related to the PCIe 3.0 lanes, liberating up all 12 lanes of PCIe 4.0 downlink for M.2 units and PCIe slots for GPUs.

There’s additionally loads of I/O straight from the CPU:

  • One PCIe x16 slot for graphics (or bifurcated to 2 x8 slots)
  • One PCIe x4 slot for M.2 NVMe SSD
  • One PCIe x4 hyperlink for discrete USB4 controller (Maple Ridge JHL8540 or ASMedia ASM4242) or M.2 NVMe SSD
  • One PCIe 4.0 x4 for chipset downlink
  • Three combo USB-C ports supporting USB3.2 Gen 2 10Gbps and DisplayPort 2.0 UHBR10 Alt Mode (every combo port may be break up into discrete DP and USB 2.0 Kind-A)
  • One extra devoted show output (DP 2.0 UHBR10 or HDMI 2.1 Mounted Fee Hyperlink or eDP)
  • One USB 3.2 Gen 2 10Gbps port with BIOS flash functionality
  • One USB 2.0 port with SecureBIO help for Home windows Hi there functionality
  • SPI/eSPI, GPIO, HD Audio

“X670E“ branded motherboards would require the first PCIe and M.2 slots to help PCIe 5.0 hyperlink price. The chipset itself is similar to X670.

With that being mentioned, listed here are the I/O block diagrams for the configuration of the B650 and X670E motherboards. These signify the best-case most supported configuration for every chipset variant, as decrease prices and smaller type issue board designs could characteristic much less I/O.

Picture supply: Angstronomics
https bucketeer e05bbc84 baa3 437e 9518 public images c11947df 28fa 44df 9c0f 55142218f797 6083x2097
Picture supply: Angstronomics


Daisy-chaining chipsets are an important concept. A daisy-chained answer drastically lowers design bills, whereas nonetheless permitting AMD to supply a number of situations of elevated I/O and efficiency capabilities with one single chipset design. 

Utilizing two median chipsets is significantly better than designing one high-end chipset and disabling options when it’s meant for the lower-end motherboards, it’s a lot simpler to double up for the high-end boards. 

Attaching two chipsets to a motherboard has different benefits, particularly over AM4. A type of benefits is that separating the load between two chipsets generates much less warmth, due to this fact the 2 chipsets require much less cooling. This additionally negates the noisy lively cooling situation. 

The second benefit is that the primary chipset acts as a sign repeater for the second chipset (when it’s arrange in a daisy-chained configuration), reducing down the price of implementing precise sign repeaters. 


The difficulty that arises with daisy-chaining chipsets collectively is that it drastically will increase the complexity of the circuit, particularly when splitting the {hardware} by virtualization between the 2 chipsets.

There’s additionally a second level of failure, we’ve by no means actually heard of a chipset taking place however in a fancy system like this, including one other level of failure might imply points down the highway if the {hardware} hasn’t been correctly examined. 

AMD has created a really advanced system right here and we’re hoping that the right measures have been taken to make sure longevity and stability inside its new AM5 motherboards. AMD has been on the rise during the last 4 or so years, and we’d wish to see that proceed. 

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