why do they put the hole so close to the middle of the connector? It makes it uselessly hard to figure out the right way to insert the module on the motherboard
You mean the alignment notch? The physical thing that keeps you from being able to install a ddr2 dimm into a ddr5 slot? The one that ensures you put the memory in the correct way and not backwards?
If there was a notch at one of the bottom corners, that would help too. Realistically, almost nobody changes out RAM now, and the only people who do so, like you and me, are people who do it multiple times, so we will learn how to tell which way round it goes. There’s a blank area on one side of the central notch, so use thy to judge which way round it is.
Two years ago a friend asked me to take a look at his first PC build to help him figure out why it wasn't working. He somehow managed to brute force his DIMM's in backwards.
I think I know why. DDR5 can read AND write at the same time unlike DDR3 and DDR4 (they had to read, wait, write, wait). So both sides can work "independently" in a way. So the notch is splitting it more evenly because it's like two kits in one. There's much more to DDR5 than just a MHz and capacity bump.
Sapphire Rapids is definitely not going to be the first DDR5 system. its targeted for Q4 2021. I highly doubt it wont be delayed further as its tied to the EUV node after intel 10nm which continues to be 90% fiction and 10% real volume. AMD/IBM or AWS w/ ARM or China would surely have something way sooner.
DDR5 support seems a reasonable assumption after 4 generations of DDR4 products.
The only question is, will it only use DDR5 - or will it also support DDR4, like those Phenom chips that supported DDR2 or 3 depending on the motherboard.
There will almost certainly be no backwards compatibility, firstly because it makes the die larger, secondly because DDR5 is a completely different beast to DDR4, thirdly because those combo boards were rare, finally because AMD will transition to AM5 for their CPUs that support DDR5.
It's not about combo boards but having the CPU's IMC support both DDR4 and DDR5, allowing you to put it in boards with either. Basically pull off what AM3 CPUs already did, with the IMC supporting DDR2 and DDR3 memory.
IBM had DDR5-specced memory controller ready for some time. Power10 is set to be *available* 2020Q3, with support for it.
I wouldn't be surprised if they enabled some P9 systems with DDR5 compatibility, like they did with 8+ (afaik it has DDR3 controller with DDR4 offchip adapter inbetween).
Maybe not part of spec, but DDR4 modules are easily selling at 3200 MHz. If DDR5 isn't clocked much higher, seems sorta pointless to buy it, although these is good for server ECC spec'd stuff.
It always seems sort of pointless at the beginning of memory generations but performance and cost significantly improve over time. DDR4 launched at 2400/2666 and was very expensive compared to DDR3; I paid over $300 for 16GB of 2666C16 when it was new on the market.
...what? First of all, 3200 is absolutely part of spec. Second, you absolutely SHOULD compare spec to spec. Second, they're talking about 4266-6400 for JEDEC DDR5. That's a huge leap when you actually compare apples-to-apples, and I imagine we'll see non-spec modules MUCH faster. There are other improvements too.
Dual 32-bit channel, while DDR4 was single 64-bit channel. So total bus width is still the same, although random access to separate 'halves' of the module can be up to 2x faster in perfect conditions.
"AMD support for DDR5 is unknown so far." While it is still unknown, the best guess would be 2021 as well. Zen 3 will apparently be the last AM4 socket Ryzen, and will be released in mid-late 2020. To support DDR5 AMD almost certainly need to change the CPU socket, and 2020 is too early anyway. So that leaves Zen 4 based Ryzen CPUs, which will require a new socket that will also support DDR5.
One either option is early DDR5 support just for Zen 3 based Epyc server CPUs. Since AMD moved the DRAM controllers to an I/O die perhaps they could do that without requiring new chiplets just for Epyc. The problem AMD has with their server line is that they keep increasing the number of cores but the memory controllers have been limited to 8, so with each generation more cores compete for the same memory access.
If they increase the cores of Zen 3 based Epyc CPUs further without DDR5 they might need to increase the memory channels to 12, and I doubt they would do that for just one server generation. So a way out would be early DDR5 support. Or no core increase. Q3/Q4 2020 might be too early for DDR5, even for servers. So they will either opt for no core increase or add one more chiplet pair for 80 cores while increasing the L3 cache and the supported DDR4 frequency further to compensate.
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38 Comments
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fred666 - Monday, January 13, 2020 - link
why do they put the hole so close to the middle of the connector? It makes it uselessly hard to figure out the right way to insert the module on the motherboardnandnandnand - Monday, January 13, 2020 - link
So that an additional pin is physically closer to memory banks?nierd - Monday, January 13, 2020 - link
You mean the alignment notch? The physical thing that keeps you from being able to install a ddr2 dimm into a ddr5 slot? The one that ensures you put the memory in the correct way and not backwards?That's a pretty useful feature.
III-V - Monday, January 13, 2020 - link
He's asking why so close to the middle, instead of closer to an edge.tipoo - Monday, January 13, 2020 - link
They're not asking why it exists, but why it's so close to the middle that it's not immediately obvious which side is which.Tomatotech - Tuesday, January 14, 2020 - link
If there was a notch at one of the bottom corners, that would help too. Realistically, almost nobody changes out RAM now, and the only people who do so, like you and me, are people who do it multiple times, so we will learn how to tell which way round it goes. There’s a blank area on one side of the central notch, so use thy to judge which way round it is.sarafino - Monday, January 20, 2020 - link
Two years ago a friend asked me to take a look at his first PC build to help him figure out why it wasn't working. He somehow managed to brute force his DIMM's in backwards.Gastec - Saturday, February 8, 2020 - link
I hope he is not driving, mistaking the brake and the acceleration pedals.Gastec - Saturday, February 8, 2020 - link
"They" :) Their majesties? Apaches?CheapSushi - Monday, January 13, 2020 - link
I think I know why. DDR5 can read AND write at the same time unlike DDR3 and DDR4 (they had to read, wait, write, wait). So both sides can work "independently" in a way. So the notch is splitting it more evenly because it's like two kits in one. There's much more to DDR5 than just a MHz and capacity bump.Rudde - Tuesday, January 14, 2020 - link
DDR5 has two independent 40 bit channels, as you suggested. DDR4 has only one channel.Manch - Tuesday, January 14, 2020 - link
50/50 chance you'll get it right if you dont look so....this is not hard...at all....Not even the slightest.willis936 - Tuesday, January 14, 2020 - link
My success rate with binary keyed connectors is less than 50%.>push USB in
>it doesn’t go in
>flip it over
>push it in
>it doesn’t go in
>flip it over
>push it in
>it goes in
HollyDOL - Wednesday, January 15, 2020 - link
Oi, that sounds so familiar :-))azfacea - Monday, January 13, 2020 - link
Sapphire Rapids is definitely not going to be the first DDR5 system. its targeted for Q4 2021. I highly doubt it wont be delayed further as its tied to the EUV node after intel 10nm which continues to be 90% fiction and 10% real volume. AMD/IBM or AWS w/ ARM or China would surely have something way sooner.eek2121 - Monday, January 13, 2020 - link
You are correct. Zen 4 will be the first product to utilize DDR5. *ducks*soresu - Monday, January 13, 2020 - link
DDR5 support seems a reasonable assumption after 4 generations of DDR4 products.The only question is, will it only use DDR5 - or will it also support DDR4, like those Phenom chips that supported DDR2 or 3 depending on the motherboard.
The_Assimilator - Tuesday, January 14, 2020 - link
There will almost certainly be no backwards compatibility, firstly because it makes the die larger, secondly because DDR5 is a completely different beast to DDR4, thirdly because those combo boards were rare, finally because AMD will transition to AM5 for their CPUs that support DDR5.close - Tuesday, January 14, 2020 - link
It's not about combo boards but having the CPU's IMC support both DDR4 and DDR5, allowing you to put it in boards with either. Basically pull off what AM3 CPUs already did, with the IMC supporting DDR2 and DDR3 memory.Vatharian - Tuesday, January 14, 2020 - link
IBM had DDR5-specced memory controller ready for some time. Power10 is set to be *available* 2020Q3, with support for it.I wouldn't be surprised if they enabled some P9 systems with DDR5 compatibility, like they did with 8+ (afaik it has DDR3 controller with DDR4 offchip adapter inbetween).
JKflipflop98 - Friday, January 17, 2020 - link
I can assure you, EUV lithography is NOT "90% fiction".webdoctors - Monday, January 13, 2020 - link
Maybe not part of spec, but DDR4 modules are easily selling at 3200 MHz. If DDR5 isn't clocked much higher, seems sorta pointless to buy it, although these is good for server ECC spec'd stuff.Destoya - Monday, January 13, 2020 - link
It always seems sort of pointless at the beginning of memory generations but performance and cost significantly improve over time. DDR4 launched at 2400/2666 and was very expensive compared to DDR3; I paid over $300 for 16GB of 2666C16 when it was new on the market.Gastec - Saturday, February 8, 2020 - link
And you will pay even more for DDR5 modules for consumer desktop. Think of $500 for 32 GBAlexvrb - Monday, January 13, 2020 - link
...what? First of all, 3200 is absolutely part of spec. Second, you absolutely SHOULD compare spec to spec. Second, they're talking about 4266-6400 for JEDEC DDR5. That's a huge leap when you actually compare apples-to-apples, and I imagine we'll see non-spec modules MUCH faster. There are other improvements too.https://www.anandtech.com/show/11238/ddr5-to-doubl...
eek2121 - Monday, January 13, 2020 - link
It's a bigger step up than you realize: DDR5 DIMMs are actually dual channel (per module).antonkochubey - Tuesday, January 14, 2020 - link
Dual 32-bit channel, while DDR4 was single 64-bit channel. So total bus width is still the same, although random access to separate 'halves' of the module can be up to 2x faster in perfect conditions.Rudde - Tuesday, January 14, 2020 - link
Isn't it dual 40 bit channel?Mugur - Tuesday, January 14, 2020 - link
For ECC only.The_Assimilator - Tuesday, January 14, 2020 - link
This engineering sample module is literally clocked more than twice the speed of launch-day DDR4 which was at 2133 MT/s...Santoval - Monday, January 13, 2020 - link
"AMD support for DDR5 is unknown so far."While it is still unknown, the best guess would be 2021 as well. Zen 3 will apparently be the last AM4 socket Ryzen, and will be released in mid-late 2020. To support DDR5 AMD almost certainly need to change the CPU socket, and 2020 is too early anyway. So that leaves Zen 4 based Ryzen CPUs, which will require a new socket that will also support DDR5.
One either option is early DDR5 support just for Zen 3 based Epyc server CPUs. Since AMD moved the DRAM controllers to an I/O die perhaps they could do that without requiring new chiplets just for Epyc. The problem AMD has with their server line is that they keep increasing the number of cores but the memory controllers have been limited to 8, so with each generation more cores compete for the same memory access.
If they increase the cores of Zen 3 based Epyc CPUs further without DDR5 they might need to increase the memory channels to 12, and I doubt they would do that for just one server generation. So a way out would be early DDR5 support. Or no core increase. Q3/Q4 2020 might be too early for DDR5, even for servers. So they will either opt for no core increase or add one more chiplet pair for 80 cores while increasing the L3 cache and the supported DDR4 frequency further to compensate.
eek2121 - Monday, January 13, 2020 - link
I mean, Ryzen 5000 series on 5nm with DDR5 and PCIE5 on 5/5 makes complete and total marketing sense. ;)AshlayW - Tuesday, January 14, 2020 - link
AM5 :DAshlayW - Tuesday, January 14, 2020 - link
5 cores, 5 threads @ 5 GHz?Too far? Yeah, because that would actually suck for my workloads vs even my 2700 @ 3.3 lol
nandnandnand - Tuesday, January 14, 2020 - link
If you want a 5-core, get that Lakefield chip with the big/small cores.I'm not sure about frequency, but Zen 4 should be good if both Zen 3 and Zen 4 bump up frequencies.
ksec - Monday, January 13, 2020 - link
Where are the 128 and 256GB DRAM?