GoKawiilAMD's long-awaited EXPO 1.2 has finally arrived on AM5 motherboards. The new and improved memory overclocking technology will allow vendors to release fast memory kits for AMD that rival the best RAM . Renowned third-party AMD utility developer 1usmus and hardware leaker chi11eddog have detailed the improvements in EXPO 1.2. However, according to the former, the most substantial benefit will likely be unlocked only with AMD's next-generation Zen 6 processors. The new version also adds support for three Chinese RAM vendors.
One of AMD EXPO 1.2's enhancements appears to be support for module geometry. While 1usmus didn’t provide extensive details, module geometry refers to the arrangement and structure of memory chips on a memory module. The feature may be related to HUDIMMs, a recent innovation that suppresses one of the 32-bit sub-channels in DDR5 memory modules, aiming to offer a cost-effective solution to the ongoing memory shortage.
AMD EXPO 1.2 introduces support for MRDIMMs (Multiplexed Rank Dual In-line Memory Modules), designed to deliver substantially higher bandwidth and greater memory capacity. These memory modules are for server and data center platforms, though, so they won't be available on consumer AM5 platforms.
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Sadly, EXPO 1.2 still only partially supports CUDIMMs (Clocked Unbuffered Dual In-line Memory Modules) and CSODIMMs (Clocked Small Outline Dual In-line Memory Modules). These modules leverage a CKD (Client Clock Driver), a small IC that maintains signal integrity and stabilizes memory operation at higher frequencies. It's a key component to help DDR5 continue to scale the frequency ladder.
However, EXPO 1.2 retains bypass mode for CUDIMMs, treating them as standard memory modules without fully leveraging the CKD's benefits. There is mention of CKD bypass modes, but we don't yet have any detailed information on them. According to 1usmus, the current AGESA 1.3.0.1 firmware does not yet fully support CUDIMMs. According to 1usmus, AMD is likely laying the groundwork for full CUDIMM support in preparation for the upcoming Ryzen 10000 processors (codenamed Olympic Ridge) that will leverage AMD's new Zen 6 execution cores.
AMD has been making significant behind-the-scenes improvements on EXPO 1.2. One of the standout features introduced is the new Ultra Low Latency (ULL) mode. It reportedly reduces memory latency. Hardware leaker chi11eddog claims that enabling ULL mode can decrease memory latency by an impressive five to seven nanoseconds on a typical DDR5-6000 memory kit.
Other improvements that EXPO 1.2 brings to the table are new fields for further fine-tuning memory that overclocking enthusiasts will appreciate. The new memory timings include tREFI, tRRDS, and tWR, along with options for VDDP voltage.
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In response to the ongoing global memory crisis, AMD has proactively expanded memory compatibility by adding support for three Chinese memory manufacturers: RAMXEED Limited Conexant, Rui Xuan (formerly known as Rei Zuan), and Fujitsu Synaptics. These brands are popular in China, but it's unlikely you'll see their memory kits in the Western markets. However, consumers who purchase Chinese memory kits from overseas via platforms such as AliExpress can expect full compatibility thanks to AMD EXPO 1.2.
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