Corsair Talks DDR5-6400 And Faster Memory Incoming For Intel Alder Lake

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Corsair is thinking bigger and faster for Alder-Lake, in fact, if it's up to Corsair, 512GB or 1 TB systems of system memory are in the vicinity. The introduction of DDR5 is very close, and it should have all kinds of advantages over DDR4

Corsair mentions that "DDR4 memory has had a great run," but it's time to get the ball rolling for the next big thing. The company says that DDR5 will bring some "key improvements for your current and future computing needs."

The DDR5 change also entails Corsair making a movie past a typical single stick size limit of 32GB to a huge 128GB. This allows mainstream motherboards to be equipped with up to 512GB of memory using four DIMM slots, while high-end 8-slot motherboards could be kitted out with 1TB of DDR5.

The DDR5 standard was officially adopted by the JEDEC umbrella organization in July 2020 . DDR5 main memory allows higher capacities for the individual chips of a module (64 instead of 16 Gbit), which consequently results in higher storage capacities per RAM bar. In the future, normal DDR5 modules (UDIMM) should even be able to offer 128 GB instead of a maximum of 32 GB as was previously the case with DDR4. JEDEC is planning a big leap in bandwidth, because at the beginning even 4.8 Gbit / s are planned, while DDR4 currently (officially) stands at a maximum of 3.2 Gbit / s. That is an increase in bandwidth of at least 50 percent. The JEDEC sees DDR5-6400 as the official maximum with 6.4 Gbit / s transfer speed. According to Corsair, the latencies for DDR5 should be comparable to DDR4.

"Overall single access latency with DDR5 is relatively unchanged, while CAS Latency has increased, the overall latency of a top-tier DDR5 kit will be similar to previous generations of DRAM clocking in at 14-15ns." And all of this is achieved while Vdd has decreased from 1.2 volts to 1.1 volts.

Corsair emphasizes that DDR5 memory modules have their own voltage regulation instead of being controlled by the mainboard. This is supposed to simplify the mainboard design and hopefully make it cheaper, but then of course the RAM bars will also be more expensive. The power management IC (PMIC) is integrated in DDR5 memory modules and, according to Corsair, this means a better power supply for each individual module and higher DRAM chip yields. This in turn should allow higher overclocking and improve the memory efficiency overall.

With DDR5, individual modules are split into two separate channels by design, allowing for shorter traces that contribute to less latency and higher speeds when it comes to communicating with individual memory ICs on a memory module. This also allows for what's referred to as command/address mirroring since the signal from the CPU has to travel a shorter overall path to access specific banks of memory whereas in DDR4 a command/address signal had to travel through all banks of memory in a longer chain.

On DDR4, when a single bank of memory needed to be refreshed, the CPU had to wait for all banks of memory on a module to refresh before doing another read or write. With DDR5, we've got double the bank groups and when a bank needs to be refreshed only the same bank of each group is refreshed, allowing for the other memory bank groups to be accessed without the CPU having to wait.

Overall single access latency with DDR5 is relatively unchanged, while CAS Latency has increased, the overall latency of a top-tier DDR5 kit will be similar to previous generations of DRAM clocking in at 14-15ns thanks to the improvements we previously mentioned.

Reliability goes down as process technologies shrink, resulting in higher latency and looser timings overall at higher speeds. DDR5 features on-die ECC as part of its spec, helping to reduce errors and allow for memory ICs to operate at higher frequencies. To be clear, this doesn't mean that mainstream DDR5 is using a full-fledged ECC implementation, there'll still be unregistered modules for typical consumer applications and ECC modules for enterprise/research applications.

Unofficial information indicates that Intel “Alder Lake” desktop processors will be in autumn 2021, the next AMD generation after “Zen 3” will support DDR5 main memory. The mass production of DDR5 memory chips has already started in the Asia region.

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