DDR5 spec finalised

HumdrumPenguin · July 18, 2020

Well, I know now that my CPU, mobo, RAM combo will be updated some time in 2022.

Kisai · July 19, 2020

On 7/16/2020 at 6:58 AM, zeusthemoose said:

Question for people with more knowledge: Are future cpus going to have to specifically support this or is that only a requirement for motherboards? Any predictions on when we will get this in consumer level hardware (hopefully based off of what happened with ddr4)?

Yes. Up until the P35/P45 Intel boards DDR2 could be used on the board, sometimes with DDR3, in separate slots. Similar kinds of transition boards existed before with 30&72pin DRAM and 144pin PC66 SDRAM. This is when the memory controller was separate from the CPU.

With the Intel and AMD boards, the CPU's only support one type of memory except in mobile applications.

LGA 1151 CPU's support DDR3/L and DDR4, but only one at a time. This is supported up to the Z270 chipset.

Z370, and z490 do not support DDR3. LGA1200 do not support DDR3. So my expectation will be either:

The transition CPU will probably be on the z590/z690 chipset going by the same naming scheme, but performance boards (eg Z series) will only have DDR5 on them, while the cheaper boards like Z510/610 will, since that's tends to be a non-US market problem in affording new memory modules.

22 hours ago, porina said:

I did think after I posted that, some level of ECC may also help them attain the higher speeds. I'm not sure how comfortable I am in that sense, we expect and allow flaws to be present and correct for them, rather than the traditional approach of not having any errors in the first place. I'm sure there are far smarter people than I who have worked out what the tolerance is so that we do not suffer a degradation in data reliability.

ECC memory refers to memory modules that have ECC hardware. It's always been a thing that some kind of parity feature can exist with non-ECC memory, this just brings it to a mandatory requirement.

Like the same issue exists with Flash memory, network cables, and wireless/RF applications. You can't get 100% accuracy the higher the bandwidth gets. With RF, particuarly WiFi, DOCSIS and DSL, there is actually a LOT of error correction going on, and people with substandard internet connectivity, this is why.

It would not surprise me if that DDR5 requires the memory modules to have heat spreaders and soldered down in a way to act as a RF shield as well.

Delicieuxz · July 19, 2020

Beyond just "2021" and then "later on", does anyone have a more specific expectation of when we'll begin to see DDR5 support for home systems?

And I'm wondering if we'll be able to buy home-user motherboards and CPUs that have support for DDR5 built into them before DDR5 RAM is available for sale. If not, I'd want to put-off building a new PC until DDR5 is available. But I'm not sure I can wait until mid or late 2021 to do so.

porina · July 19, 2020

4 minutes ago, Delicieuxz said:

Beyond just "2021" and then "later on", does anyone have a more specific expectation of when we'll begin to see DDR5 support for home systems?

And I'm wondering if we'll be able to buy home-user motherboards and CPUs that have support for DDR5 built into them before DDR5 RAM is available for sale. If not, I'd want to put-off building a new PC until DDR5 is available. But I'm not sure I can wait until mid or late 2021 to do so.

At best we can guess. We don't know what the industry as a whole will do. Chances are, those with an interest in DDR5 would already have been working on it while it was a draft standard, so it isn't like they have to start working on it now. The industry will coordinate somewhat so that parts will be made available at a similar time. After all, there is no point selling one part if the other needed to go with it isn't there.

If we look at Intel, they only released Comet Lake earlier this year. Typically its successor will be around another year. That might still be too early for DDR5, so maybe look for the generation after that in 2022. On AMD side, we may get Zen 3 towards the end of this year. Zen 4 would seem about the right time frame, putting it towards end of next year, or early 2022. Either side may be earlier or later for many reasons.

I think if you need a new system, get a new system now (with a door open for Zen 3 should it pop up). It will be DDR4, but I'd guess you'll probably get 18 months out of it before DDR5 is even available. You can evaluate if it is worth upgrading at that point. Unless you have some very ram bandwidth demanding tasks that really needs it, it doesn't seem worth waiting for in itself.