GoKawiilEXPO 1.2 officially released two days ago with Asus' X870 models being among the first recipients of the new feature. The company is expanding support to more X870 and even B850 models with beta BIOS builds, while teasing that older X670 and B650 motherboards are also due for an upgrade. EXPO 1.2 brings a range of improvements with the main feature being CUDIMM support, allowing for significantly higher DDR5 memory speeds.
Unlike standard UDIMMs that needs to constantly talk to the CPU's memory controller, CUDIMM comes with a CKD (Client Clock Driver) that lets the RAM maintain signal integrity and stabilizes memory operation at higher frequencies. EXPO 1.2 adds partial support for CUDIMM, allowing them to run in "bypass mode" that limits the speeds to around 6,000 MT/s despite being capable of achieving up to 9,000 MT/s.
Ryzen 7000, 8000G, and 9000 series processors don't natively support CUDIMM. So even though the motherboard will recognize it with new AGESA updates, the memory controller won't let the system boot without the bypass mode. Native CUDIMM compatibility is reportedly planned for next-gen Ryzen CPUs based on the Zen 6 architecture. In contrast, Intel's Arrow Lake chips have native CUDIMM support.
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CUDIMM also brings Ultra-Low Latency mode for DDR5 memory, reducing it by five to seven nanoseconds. MRDIMM support is also being added for data center and server CPUs that should allow for much higher throughput. A more interesting feature for consumers is perhaps the added support for module geometry that can understand how the ICs are arranged on individual DDR5 sticks. This could enable HUDIMM support on AM5.
(Image credit: Future)
EXPO 1.2 is currently available on only AMD's latest 800-series motherboards across different vendors, but Asus has implied that older 600-series models, such as X670 and B650, could also get the updates soon. The screenshot above is from the ROG forums hosting the beta BIOSes, so this is not an official confirmation but a positive sign nonetheless for early adopters of the platform. Apart from the obvious CUDIMM omission, users should still be able to benefit from EXPO 1.2's other improvements.
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