The compute market has always been hungry for memory bandwidth, particularly for high-performance applications in servers and datacenters. In recent years, the explosion in core counts per socket has further accentuated this need. Despite progress in DDR speeds, the available bandwidth per core has unfortunately not seen a corresponding scaling.
The stakeholders in the industry have been attempting to address this by building additional technology on top of existing widely-adopted memory standards. With DDR5, there are currently two technologies attempting to increase the peak bandwidth beyond the official speeds. In late 2022, SK hynix introduced MCR-DIMMs meant for operating with specific Intel server platforms. On the other hand, JEDEC - the standards-setting body - also developed specifications for MR-DIMMs with a similar approach. Both of them build upon existing DDR5 technologies by attempting to combine multiple ranks to improve peak bandwidth and latency.
The MR-DIMM standard is conceptually simple - there are multiple ranks of memory modules operating at standard DDR5 speeds with a data buffer in front. The buffer operates at 2x the speed on the host interface side, allowing for essentially double the transfer rates. The challenges obviously lie in being able to operate the logic in the host memory controller at the higher speed and keeping the power consumption / thermals in check.
The first version of the JEDEC MR-DIMM standard specifies speeds of 8800 MT/s, with the next generation at 12800 MT/s. JEDEC also has a clear roadmap for this technology, keeping it in sync with the the improvements in the DDR5 standard.
Micron and Intel have been working closely in the last few quarters to bring their former's first-generation MR-DIMM lineup to the market. Intel's Xeon 6 Family with P-Cores (Granite Rapids) is the first platform to bring MR-DIMM support at 8800 MT/s on the host side. Micron's standard-sized MR-DIMMs (suitable for 1U servers) and TFF (tall form-factor) MR-DIMMs (for 2U+ servers) have been qualified for use with the same.
The benefits offered by MR-DIMMs are evident from the JEDEC specifications, allowing for increased data rates and system bandwidth, with improvements in latency. On the capacity side, allowing for additional ranks on the modules has enabled Micron to offer a 256 GB capacity point. It must be noted that some vendors are also using TSV (through-silicon vias) technology to to increase the per-package capacity at standard DDR5 speeds, but this adds additional cost and complexity that are largely absent in the MR-DIMM manufacturing process.
The tall form-factor (TFF) MR-DIMMs have a larger surface area compared to the standard-sized ones. For the same airflow configuration, this allows the DIMM to have a better thermal profile. This provides benefits for energy efficiency as well by reducing the possibility of thermal throttling.
Micron is launching a comprehensive lineup of MR-DIMMs in both standard and tall form-factors today, with multiple DRAM densities and speed options as noted above.
Micron and Intel hosted a media / analyst briefing recently to demonstrate the benefits of MR-DIMMs for Xeon 6 with P-Cores (Granite Rapids). Using a 2P configuration with 96-core Xeon 6 processors, benchmarks for different ... Memory
As LPCAMM2 adoption begins, the first retail memory modules are finally starting to hit the retail market, courtesy of Micron. The memory manufacturer has begun selling their LPDDR5X-based LPCAMM2 memory modules under their in-house Crucial brand, making them available on the latter's storefront. Timed to coincide with the release of Lenovo's ThinkPad P1 Gen 7 laptop – the first retail laptop designed to use the memory modules – this marks the de facto start of the eagerly-awaited modular LPDDR5X memory era.
Micron's Low Power Compression Attached Memory Module 2 (LPCAMM2) modules are available in capacities of 32 GB and 64 GB. These are dual-channel modules that feature a 128-bit wide interface, and are based around LPDDR5X memory running at data rates up to 7500 MT/s. This gives a single LPCAMM2 a peak bandwidth of 120 GB/s. Micron is not disclosing the latencies of its LPCAMM2 memory modules, but it says that high data transfer rates of LPDDR5X compensate for the extended timings.
Micron says that LPDDR5X memory offers significantly lower power consumption, with active power per 64-bit bus being 43-58% lower than DDR5 at the same speed, and standby power up to 80% lower. Meanwhile, similar to DDR5 modules, LPCAMM2 modules include a power management IC and voltage regulating circuitry, which provides module manufacturers additional opportunities to reduce power consumption of their products.

Source: Micron LPDDR5X LPCAMM2 Technical Brief
It's worth noting, however, that at least for the first generation of LPCAMM2 modules, system vendors will need to pick between modularity and performance. While soldered-down LPDDR5X memory is available at speeds up to 8533 MT/sec – and with 9600 MT/sec on the horizon – the fastest LPCAMM2 modules planned for this year by both Micron and rival Samsung will be running at 7500 MT/sec. So vendors will have to choose between the flexibility of offering modular LPDDR5X, or the higher bandwidth (and space savings) offered by soldering down their memory.
Micron, for its part, is projecting that 9600 MT/sec LPCAMM2 modules will be available by 2026. Though it's all but certain that faster memory will also be avaialble in the same timeframe.
Micron's Crucial LPDDR5X 32 GB module costs $174.99, whereas a 64 GB module costs $329.99.
Memory
While the new CAMM and LPCAMM memory modules for laptops have garnered a great deal of attention in recent months, it's not just the mobile side of the PC memory industry that is looking at changes. The desktop memory market is also coming due for some upgrades to further improve DIMM performance, in the form of a new DIMM variety called the Clocked Unbuffered DIMM (CUDIMM). And while this memory isn't in use quite yet, several memory vendors had their initial CUDIMM products on display at this year's Computex trade show, offering a glimpse into the future of desktop memory.
A variation on traditional Unbuffered DIMMs (UDIMMs), Clocked UDIMMs (and Clocked SODIMMs) have been created as another solution to the ongoing signal integrity challenges presented by DDR5 memory. DDR5 allows for rather speedy transfer rates with removable (and easily installed) DIMMs, but further performance increases are running up against the laws of physics when it comes to the electrical challenges of supporting memory on a stick – particularly with so many capacity/performance combinations like we see today. And while those challenges aren't insurmountable, if DDR5 (and eventually, DDR6) are to keep increasing in speed, some changes appear to be needed to produce more electrically robust DIMMs, which is giving rise to the CUDIMM.
Standardized by JEDEC earlier this year as JESD323, CUDIMMs tweak the traditional unbuffered DIMM by adding a clock driver (CKD) to the DIMM itself, with the tiny IC responsible for regenerating the clock signal driving the actual memory chips. By generating a clean clock locally on the DIMM (rather than directly using the clock from the CPU, as is the case today), CUDIMMs are designed to offer improved stability and reliability at high memory speeds, combating the electrical issues that would otherwise cause reliability issues at faster memory speeds. In other words, adding a clock driver is the key to keeping DDR5 operating reliably at high clockspeeds.
All told, JEDEC is proposing that CUDIMMs be used for DDR5-6400 speeds and higher, with the first version of the specification covering speeds up to DDR5-7200. The new DIMMs will also be drop-in compatible with existing platforms (at least on paper), using the same 288-pin connector as today's standard DDR5 UDIMM and allowing for a relatively smooth transition towards higher DDR5 clockspeeds.
MemoryDuring the Intel keynote hosted by CEO Pat Gelsinger, he gave the world a glimpse into the Intel Client roadmap until 2026. Meteor Lake launched last year on that roadmap, and Lunar Lake, which we dived into yesterday as Intel disclosed technical details about the upcoming platform. Pat also presented a wafer on stage, Panther Lake, and he gave some additional information about Intel's forthcoming Panther Lake platform, which is expected in 2025.
We covered Intel's initial announcement about the Panther Lake platform last year. It is set to be Intel's first client platform using its Intel 18A node. Aside from once again affirming that things are on track for a 2026 launch, Pat Gelsinger, Intel's CEO, also confirmed that they will be powering on the first 18A wafer for Panther Lake as early as next week.
| Intel CPU Architecture Generations | |||||
| Alder/Raptor Lake | Meteor Lake |
Lunar Lake |
Arrow Lake |
Panther Lake |
|
| P-Core Architecture | Golden Cove/ Raptor Cove |
Redwood Cove | Lion Cove | Lion Cove | Cougar Cove? |
| E-Core Architecture | Gracemont | Crestmont | Skymont | Crestmont? | Darkmont? |
| GPU Architecture | Xe-LP | Xe-LPG | Xe2 | Xe2? | ? |
| NPU Architecture | N/A | NPU 3720 | NPU 4 | ? | ? |
| Active Tiles | 1 (Monolithic) | 4 | 2 | 4? | ? |
| Manufacturing Processes | Intel 7 | Intel 4 + TSMC N6 + TSMC N5 | TSMC N3B + TSMC N6 | Intel 20A + More | Intel 18A + ? |
| Segment | Mobile + Desktop | Mobile | LP Mobile | HP Mobile + Desktop | Mobile? |
| Release Date (OEM) | Q4'2021 | Q4'2023 | Q3'2024 | Q4'2024 | 2025 |
One element to consider from last year is that Lunar Lake is built using TSMC, with the Lunar Lake compute tile with Xe2-LPG graphics on TSMC N3B, and the I/O tile on TSMC N6. Pat confirmed on stage that Panther Lake will be on Intel 18A. Still, he didn't confirm whether the chip will be made purely at Intel, or a mix between Intel and external foundries (ala Meteor Lake). Intel has also yet to confirm the CPU cores to be used, but from what our sources tell us, it sounds like it will be the new Cougar Cove and Darkmont cores.
As we head into the second half of 2024 and after Lunar Lake launches, Intel may divulge more information, including the architectural advancements Panther Lake is expected to bring. Until then, we will have to wait and see.
CPUs
0 Comments