PC DDR6 Memory to Offer 10-times the Bandwidth of DDR4: Synopsys

[btarunr]

The next-generation PC DDR6 memory standard (not to be confused with GDDR6), will offer a 10-times increase in bandwidth over DDR4, according to a presentation by Synopsys, a major vendor of memory controller and PHY IP blocks. The initial draft of DDR6 specification by JEDEC is expected to be ready within 2024, with version 1.0 of the spec ready by mid-2025. Speeds (data-rates) of DDR6 start at DDR6-8800, and range up to DDR6-17600 in the first generation; with future generations of DDR6 going all the way up to DDR6-21333 (or 21 Gbps). This is exactly 10 times the bandwidth of DDR4-2133, the initial speed of DDR4 that debuted with 6th Gen Core "Skylake" processors, almost a decade ago. It hence makes sense for a memory specification 10 years since to offer such a linear scaling in bandwidth.

Synopsys also talks about LPDDR6 in this presentation, the future low power memory standard for thin-and-light computing devices and smartphones. LPDDR6 will have an introductory data-rate of LPDDR6-10667 over a 24-bit memory channel, with two 12-bit sub-channels. The highest defined data-rate for LPDDR6 is expected to be LPDDR6-14400 (likely 14466 MT/s). Besides generational increases in bandwidth, both PC DDR6 and LPDDR6 are expected to introduce several security and energy-efficiency features, including an "efficiency mode" that reduces idle power draw for the memory devices.



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[JWNoctis]

Why 12/24-bit channels? 8b or 16b encoded and with ECC?

Recall how fast DDR5 was supposed to go, by JEDEC specification. I don't remember seeing the faster numbers often, outside some server and workstation modules in non-XMP/EXPO context.

 

[londiste]

Stupid headline. DDR6-21333 in the future (maybe) vs DDR4-2133.
The performance for the baseline spec for each RAM generation usually doubles and this the case here as well - The DDR6 baseline of DDR6-8800 is a bit over 4 times faster than DDR4-2133 and roughly twice as fast as DDR5-4000.

 

[ARF]

And yet, when you switch your PC on, you will hardly notice any performance improvement, as is the case of 500 MB/s SATA SSD vs. 7000 MB/s PCIe 4.0 x4 M.2 NVMe SSD.

 

[wolf]

with future generations of DDR6 going all the way up to DDR6-21333 (or 21 Gbps).

Wouldn't that be 21 GT/s (gigatransfers per second) not Gbps?

 

[JWNoctis]

And yet, when you switch your PC on, you will hardly notice any performance improvement, as is the case of 500 MB/s SATA SSD vs. 7000 MB/s PCIe 4.0 x4 M.2 NVMe SSD.

Arguably there's a limit, when it often spends more time on password prompt, or in BIOS training memory/restoring memory training/doing whatever it is ME or PSP do/doing something else.

 

[stimpy88]

And probably 10x the latency. Even 3D cache won't be enough for this rubbish!

And yet, when you switch your PC on, you will hardly notice any performance improvement, as is the case of 500 MB/s SATA SSD vs. 7000 MB/s PCIe 4.0 x4 M.2 NVMe SSD.

Erm... Not my experience, at all. Unless we are only talking Windows boot performance.

 

[ARF]

And probably 10x the latency.

Nope, the CAS latency in nanoseconds always remains between 12.5 and 15. No matter the type of the memory module.

 

[tpu7887]

Technically DDR6 will have 10x the bandwidth of DDR3. Most people think 1333/1600 with DDR3, but JEDEC spec was 800/1066/1333/1600/1866/2133

Bulldozer and its two follow-ups, the APU versions wanted 1866 and 2133. Having 34GB/s of video memory (although shared with the CPU) was a pretty big boost to performance compared to Intel's IGPs typically 1066/1333/1600. None of their CPUs officially supported 2133 DDR3, but every chip going back to Sandy Bridge supported it.

I still use my 2500K @ 4.7GHz and 1.38V with 32GB DDR3 2133 running 10-12-11 CL1. It's four dual rank sticks, so not 100% ideal, but pretty close! 9.37ns latency


Anyway, yeah - so while DDR4 did debut at 2133, DDR3 already existed at 2133, and it wasn't an overclocked variant. OC DDR3 actually went all the way through and past DDR4 spec - into 4's overclocking range! I remember seeing a DDR3 3400 kit, 200 faster than DDR4's fastest speed of 3200!

 

[kondamin]

Damn 4 years and they are done with ddr5, if I had known I could have skipped an entire memory generation

 

[Chomiq]

Damn 4 years and they are done with ddr5, if I had known I could have skipped an entire memory generation

I mean, it's still probably 2 or 3 years before DDR6 is widely adapted and then you also have to consider the prices being super high after launch plus latency issues etc. But hey, I'll probably hold on to my AM4 platform until AM6 is launched.

 

[ARF]

Technically DDR6 will have 10x the bandwidth of DDR3. Most people think 1333/1600 with DDR3, but JEDEC spec was 800/1066/1333/1600/1866/2133

Bulldozer and its two follow-ups, the APU versions wanted 1866 and 2133. Having 34GB/s of video memory (although shared with the CPU) was a pretty big boost to performance compared to Intel's IGPs typically 1066/1333/1600. None of their CPUs officially supported 2133 DDR3, but every chip going back to Sandy Bridge supported it.

I still use my 2500K @ 4.7GHz and 1.38V with 32GB DDR3 2133 running 10-12-11 CL1. It's four dual rank sticks, so not 100% ideal, but pretty close! 9.37ns latency


Anyway, yeah - so while DDR4 did debut at 2133, DDR3 already existed at 2133, and it wasn't an overclocked variant. OC DDR3 actually went all the way through and past DDR4 spec - into 4's overclocking range! I remember seeing a DDR3 3400 kit, 200 faster than DDR4's fastest speed of 3200!

This only proves that the memory standards are not fully exploited, but rather AMD hurries to jump on "new" things because "moar (higher number)" is "better".

I mean, it's still probably 2 or 3 years before DDR6 is widely adapted and then you also have to consider the prices being super high after launch plus latency issues etc. But hey, I'll probably hold on to my AM4 platform until AM6 is launched.

It is 2 or 3 years before any new products support it.
Even today, the best seller is still DDR4-3200, and that won't change anytime soon, despite DDR5 or distant future DDR6.

Amazon Best Sellers: Best Computer Memory

Discover the best Computer Memory in Best Sellers. Find the top 100 most popular items in Amazon Computers & Accessories Best Sellers.

www.amazon.com

 

[Endymio]

... It hence makes sense for a memory specification 10 years since to offer such a linear scaling in bandwidth.

Who writes these articles? The fact that the numeral "10" appears in both the years and the bandwidth factor doesn't make the scaling 'linear' over that period. And if one picks only two points in time, you'll discover a linear relationship between the two, simply because two points define a line.

 

[londiste]

Technically DDR6 will have 10x the bandwidth of DDR3. Most people think 1333/1600 with DDR3, but JEDEC spec was 800/1066/1333/1600/1866/2133

Did you mean less than 4x the bandwidth of DDR3?
DDR3-2133 vs DDR6-8000

 

[Endymio]

Did you mean less than 4x the bandwidth of DDR3?
DDR3-2133 vs DDR6-8000

The numeric figure in the spec indicates MT/s, (transfers) not bandwidth. DDR3-2133 is 17GB/sec, whereas DDR6-8000 is, if I calculate correctly, 134 GB/sec.

 

[londiste]

The numeric figure in the spec indicates MT/s, (transfers) not bandwidth. DDR3-2133 is 17GB/sec, whereas DDR6-8000 is, if I calculate correctly, 134 GB/sec.

DDR3-2133 vs DDR6-8000 is a comparison of MT/s. Assuming the same memory bus width the difference in MB/s is the same. On desktop there are no indications of bus width changing and for a proper comparison it is nice to compare at the same width.

Assuming 64-bit memory bus:
8000MT/s is 8 000 * 64 = 512 000 Mb/s = 64 000 MB/s = 62.5 GB/s
2133MT/s is 2 133 * 64 = 136 512 Mb/s = 17 064 MB/s = 16.66 GB/s

 

[Endymio]

DDR3-2133 vs DDR6-8000 is a comparison of MT/s. Assuming the same memory bus width the difference in MB/s is the same.

DDR3 is dual channel (as is DDR4/5). DDR6 is quad-channel. Double again your calculated bandwidth and you get the correct figure.

 

[londiste]

DDR3 is dual channel (as is DDR4/5). DDR6 is quad-channel. Double again your calculated bandwidth and you get the correct figure.

So far I have seen this described as subchannels - similarly to DDR5 having two 32-bit subchannels, DDR6 plans involve having four (supposedly) 16-bit subchannels per 64-bit module.

DDR3 is not inherently dual-channel. Memory modules have been 64-bit for a while and having multiple channels is a memory controller thing.
IMCs on desktop tend to be dual-channel today but same modules are used for other configurations, usually in servers. For example DDR3 was used in quad-channel on X79 - Sandy-E/Ivy-E Xeons.
Latest Epycs can do 12-channel DDR5 if I remember correctly.

 

[tpu7887]

Did you mean less than 4x the bandwidth of DDR3?
DDR3-2133 vs DDR6-8000

If you pick the lowest speed maybe lol

 

[chrcoluk]

DDR5 only came out 5 minutes ago, its so new it still has early adopter problems, I dont want DDR to go the same rapid path of PCIe.

Damn 4 years and they are done with ddr5, if I had known I could have skipped an entire memory generation

Thinking the same, DDR5 probably wont make it on any of my systems now, it become like CPU and GPU where missing generations.

 

[tpu7887]

This only proves that the memory standards are not fully exploited, but rather AMD hurries to jump on "new" things because "moar (higher number)" is "better".



It is 2 or 3 years before any new products support it.
Even today, the best seller is still DDR4-3200, and that won't change anytime soon, despite DDR5 or distant future DDR6.

Amazon Best Sellers: Best Computer Memory

Discover the best Computer Memory in Best Sellers. Find the top 100 most popular items in Amazon Computers & Accessories Best Sellers.

www.amazon.com

AMD tried to focus on their strength, which was definitely not IPC at that time, especially after Sandy Bridge! While Intel HD graphics 3000 was Intel's first decent integrated solution, AMD, having ATi's GPU experience, beat it by a pretty large margin - double to triple if memory serves. DDR3 2133 was supported by AMD's chips, but only really recommended for specific CPU workloads with 8 cores, or for the APUs to feed both the CPU and GPU sufficiently-to prevent bottlenecks. And to allow some AA.

Sandy Bridge was speculated to be spec'd to run at up to 2133 in 09/10, but I think when Intel realised in that none of their CPUs until DDR4 would be pushing much past 2133, they decided to artificially limit Sandy to dual channel 1333 (so Ivy could be 1600 and Haswell/Broadwell could be 1866/2133. Broadwell on the crappy node shrink might have been why its max official supported speed remained at 1866 - idk for sure.

 

[Enterprise24]

Technically DDR6 will have 10x the bandwidth of DDR3. Most people think 1333/1600 with DDR3, but JEDEC spec was 800/1066/1333/1600/1866/2133

Bulldozer and its two follow-ups, the APU versions wanted 1866 and 2133. Having 34GB/s of video memory (although shared with the CPU) was a pretty big boost to performance compared to Intel's IGPs typically 1066/1333/1600. None of their CPUs officially supported 2133 DDR3, but every chip going back to Sandy Bridge supported it.

I still use my 2500K @ 4.7GHz and 1.38V with 32GB DDR3 2133 running 10-12-11 CL1. It's four dual rank sticks, so not 100% ideal, but pretty close! 9.37ns latency


Anyway, yeah - so while DDR4 did debut at 2133, DDR3 already existed at 2133, and it wasn't an overclocked variant. OC DDR3 actually went all the way through and past DDR4 spec - into 4's overclocking range! I remember seeing a DDR3 3400 kit, 200 faster than DDR4's fastest speed of 3200!

I think you are doing a great job. 2133 is the max limit for Sandy Bridge. Never seen any chip even on hwbot able to run 2400 apart from Sandy Bridge-E. I myself was running two sticks of single rank 2x4GB 2133 9-11-10-27-1T with 2600k @ 4.8Ghz. But I never think that the IMC is able to push 4 sticks of dual ranks memory to 2133.

 

[mechtech]

I'll wait for ddr6-12800 jedec

 

[Minus Infinity]

I mean, it's still probably 2 or 3 years before DDR6 is widely adapted and then you also have to consider the prices being super high after launch plus latency issues etc. But hey, I'll probably hold on to my AM4 platform until AM6 is launched.

I'll bet even Nova Lake doesn't have DDR6 support in late 2026. Probably have to wait for its successor or Zen 7 before we get MB's supporting it and they'll offer DDR5 support as well IMO.

 

[Wirko]

Why 12/24-bit channels? 8b or 16b encoded and with ECC?

Strange indeed, and ECC isn't mentioned. What's a CPU supposed to do with 1.5 byte units when the smallest unit of transfer is 64 bytes, or one cache line?
Also ... Does LPDDR with ECC even exist?

Assuming 64-bit memory bus:
8000MT/s is 8 000 * 64 = 512 000 Mb/s = 64 000 MB/s = 62.5 GB/s

Yeah but what flavour of "G" is that? When describing data rates, mega/giga/tera is always, universally, decimal (powers of 1000), not binary (powers of 1024). Your M here is 1,000,000 but your G is 1,024,000,000.