Why don't AM4 DDR5 motherboards exist?

[setsakara]

I was planning a build using the 3600XT, and wondered if I could have DDR5 in it. I scrounged far and wide, but NO DDR5 am4 motherboards. How come?

 

The closest to DDR5 you can get with DDR4 is 4600MHz RAM or 4800MHz U-DIMM RAM.

[Middcore]

Do you understand that the AM4 platform was launched in early 2017?

 

 

[Needfuldoer]

There are no AM4 processors that support DDR5.

[setsakara]

Yes, but still some AM4 boards still being produced, and LGA1200 DDR5 boards exist

[setsakara]

Just now, Needfuldoer said:

There are no AM4 processors that support DDR5.

Got it, thanks

[glenalz81]

6 minutes ago, setsakara said:

The closest to DDR5 you can get with DDR4 is 4600MHz RAM or 4800MHz U-DIMM RAM.

DDR4 5000+ exsists in a few kits. Doesn't really matter anyway the CPU's don't support DDR5.

Fastest realistic speed you could run on your 3600XT is 3800MHz C14 on Samsung B-Die or C16 on Micron Rev E.

[Needfuldoer]

2 minutes ago, setsakara said:

Yes, but still some AM4 boards still being produced, and LGA1200 DDR5 boards exist

LGA 1700 motherboards come in DDR4 and DDR5 varieties because Alder Lake and Rocket Lake support both DDR4 and DDR5.

[IkeaGnome]

2 minutes ago, setsakara said:

and LGA1200 DDR5 boards exist

Mind showing me one? Are you sure you don't mean LGA 1700? Intel 12th and 13th gen are meant to be a middle ground for DDR4 and DDR5. Want to still run DDR4? You can. Want to run DDR5? You can.

AMD isn't going that route with AM5. Amd is DDR4 OR DDR5 only. 

[Middcore]

4 minutes ago, setsakara said:

and LGA1200 DDR5 boards exist

 

No, they don't.

 

I also don't know why you're bringing up LGA 1200 anyway. The current Intel socket when AM4 was launched was LGA 1151 "v2" so you may as well ask why it doesn't support DDR5. The answer would be the same: no CPU's for those sockets support DDR5, nor could they, as the DDR5 standard wasn't even finalized then. 

[setsakara]

1 minute ago, glenalz81 said:

DDR4 5000+ exsists in a few kits. Doesn't really matter anyway the CPU's don't support DDR5.

Fastest realistic speed you could run on your 3600XT is 3800MHz C14 on Samsung B-Die or C16 on Micron Rev E.

I was gonna try to do 4600MHz RAM on it, does that mean I can't?

[setsakara]

Just now, Middcore said:

 

No, they don't.

 

I also don't know why you're bringing up LGA 1200 anyway. The current Intel socket when AM4 was launched was LGA 1151 "v2" so you may as well ask why it doesn't support DDR5. The answer would be the same: no CPU's for those sockets support DDR5. The DDR5 standard wasn't even finalized then. 

I'll just shut up now ;-;

I'll go learn more before posting again <_>

[mariushm]

DDR5 memory slots have a different number of contacts / pins compared to DDR4 

If you want to support the same number of memory slots, you would need more contacts/pins in the CPU socket, or at the very least to re-purpose some of the existing pins in the CPU socket.

Also, from an electrical point of view (how "wires" inside the motherboard are routed between the cpu socket and the memory slots, how insulated the signals are from other signals),  it's MUCH harder to make motherboards that support DDR5 - the signals often have to be separated into multiple layers of the motherboard to get more insulation from other signals and to achieve those high frequencies without or with minimal transfer errors.

So even if they could repurpose some pins in the CPU socket to make DDR5 possible, the existing motherboards would have a very difficult time using the memory, and at best you'd only be able to use DDR5 sticks at the lowest frequencies, without stability issues.

 

The extra numbers of layers in the motherboard, the better fiber glass material required to support DDR5, means the motherboards will be more expensive.

 

You would also have to work super hard to add more to the BIOSes, make them work with both DDR4 and DDR5, that means a lot more work.

 

So it's better to just say NO  and leave AM4 with only DDR4 support, and make DDR5 only work on AM5 socket.

 

PS.  Also, it's not really worth going with more than 3600 Mhz DDR4 sticks, because the internals of the CPU work at that frequency, so when everything is in sync everything works well.

 

 

[glenalz81]

2 minutes ago, setsakara said:

I was gonna try to do 4600MHz RAM on it, does that mean I can't?

Infinity fabric (FCLK) tops out on AM4 CPUs at around 1900, if you're really really lucky you may get 2000 which would mean RAM at 4000 may work but those chips are few and far between.  The infinty fabric runs 1:1 with RAM speed, if you don't run it 1:1 (out of sync)  you lose performance.

Sweet spot is 3733 RAM and 1866 FCLK, most chips will do this. With a bit of tuning then 3800 and 1900 is mostly doable.

My advice is to buy a 3200 C14 b-die kit and overclock to 3800, or get a Ballistix kit of 3600 C16 and again OC to 3800.  There's plenty of copy/paste settings round the internet for those kits.

[setsakara]

3200MHz is still enough? Will it be future-proof?

Does that mean I can still use 4600MHz? or should I upgrade to a 5000 series?

I really like the 3600XT, they're rare and perform great

 

I really like the 4600MHz kits because they would allow me to overclock to DDR5 frequencies, and would also make it so I wouldn't have to upgrade for a while.

[mariushm]

You can still use 4600 Mhz DDR4 , but you may actually get slightly more performance if you configure it at 3700-3800 Mhz and lower CL timings. So if you do that, you may just as well save money and go with 3200-3600 mhz.

 

At 3600-3800 Mhz, the memory will run at 1:1 ratio (one tick of infinity fabric, one tick of memory) ... but if you leave it at 4600 that 1:1 ratio will change to another ratio, which can result in a bit lower performance under some conditions.

 

[setsakara]

21 minutes ago, IkeaGnome said:

Mind showing me one? Are you sure you don't mean LGA 1700? Intel 12th and 13th gen are meant to be a middle ground for DDR4 and DDR5. Want to still run DDR4? You can. Want to run DDR5? You can.

AMD isn't going that route with AM5. Amd is DDR4 OR DDR5 only. 

Sorry I angered you, my goal was really just to try to gain more information ;-;

I guess I'll just shut up now

[setsakara]

2 minutes ago, mariushm said:

You can still use 4600 Mhz DDR4 , but you may actually get slightly more performance if you configure it at 3700-3800 Mhz and lower CL timings. So if you do that, you may just as well save money and go with 3200-3600 mhz.

 

At 3600-3800 Mhz, the memory will run at 1:1 ratio (one tick of infinity fabric, one tick of memory) ... but if you leave it at 4600 that 1:1 ratio will change to another ratio, which can result in a bit lower performance under some conditions.

 

https://www.amazon.com/PNY-4600MHz-PC4-36800-Channel-Desktop/dp/B09DTLPPSN

This is $100 for 4600MHz

I can afford that easily

16GB is all I need really, I can also upgrade to a 4-module 32GB config 

[setsakara]

17 minutes ago, mariushm said:

DDR5 memory slots have a different number of contacts / pins compared to DDR4 

If you want to support the same number of memory slots, you would need more contacts/pins in the CPU socket, or at the very least to re-purpose some of the existing pins in the CPU socket.

Also, from an electrical point of view (how "wires" inside the motherboard are routed between the cpu socket and the memory slots, how insulated the signals are from other signals),  it's MUCH harder to make motherboards that support DDR5 - the signals often have to be separated into multiple layers of the motherboard to get more insulation from other signals and to achieve those high frequencies without or with minimal transfer errors.

So even if they could repurpose some pins in the CPU socket to make DDR5 possible, the existing motherboards would have a very difficult time using the memory, and at best you'd only be able to use DDR5 sticks at the lowest frequencies, without stability issues.

 

The extra numbers of layers in the motherboard, the better fiber glass material required to support DDR5, means the motherboards will be more expensive.

 

You would also have to work super hard to add more to the BIOSes, make them work with both DDR4 and DDR5, that means a lot more work.

 

So it's better to just say NO  and leave AM4 with only DDR4 support, and make DDR5 only work on AM5 socket.

 

PS.  Also, it's not really worth going with more than 3600 Mhz DDR4 sticks, because the internals of the CPU work at that frequency, so when everything is in sync everything works well.

 

 

when did I ever say I was gonna try to put DDR4 in a DDR5 board or DDR5 in a DDR4 board

 

also is it possible to "underclock" ram by making it run at a lower frequency?

Just a dumb question

[IkeaGnome]

10 minutes ago, setsakara said:

Sorry I angered you, my goal was really just to try to gain more information ;-;

I guess I'll just shut up now

That wasn't meant to come across as me angry. I was actually curious what 1200 board you saw that advertised DDR5. 

[mariushm]

I said in general, the post was not about you.

In general people are dumb and will try to force ddr5 sticks into ddr4 slots and other such foolishness.

 

Yes, actually if you want to know, the 4600 Mhz is considered "factory overclocking"  or "overclocking condoned by the manufacturer of the sticks"

The tiny ram chips on the stick are made by various companies (Samsung, Hynix, Micron) and they test them at speeds like 2666 Mhz, 3000 Mhz , 3600 Mhz and they put the chips in different bins depending on how good they are at those frequencies.

So a manufacturer like Corsair or Kingston or whatever buys 100k chips that the manufacturer guarantees they work at 3200 Mhz and 1.2v and they individually test them at higher frequencies and higher voltages and looser timings.

 

So out of 100k tiny chips, maybe 10k chips can function at 4600 Mhz but higher voltage (like 1.45v for example) and looser timings, so they make a stick out of 8-16 such chips and put in the stick a XMP profile (a list of parameters) that the bios can read and apply. 

As required for most compatibility, the sticks will still have standard profiles stored in them, for standard frequencies like 2666 Mhz, 3200 Mhz, 3600 Mhz and also with tighter timings.

If the motherboard knows it's not designed well enough to support 4600 Mhz sticks, the bios will look in the list of profiles and pick the next most suitable. If nothing is suitable, the bios will pick a profile that's hardcoded within the bios, for a standard frequency like 2133 Mhz or 2400 Mhz, and you'd have to force a  profile manually.

[setsakara]

I'm really sorry

also nice PC you have

 

[setsakara]

1 minute ago, mariushm said:

I said in general, the post was not about you.

In general people are dumb and will try to force ddr5 sticks into ddr4 slots and other such foolishness.

 

Yes, actually if you want to know, the 4600 Mhz is considered "factory overclocking"  or "overclocking condoned by the manufacturer of the sticks"

The tiny ram chips on the stick are made by various companies (Samsung, Hynix, Micron) and they test them at speeds like 2666 Mhz, 3000 Mhz , 3600 Mhz and they put the chips in different bins depending on how good they are at those frequencies.

So a manufacturer like Corsair or Kingston or whatever buys 100k chips that the manufacturer guarantees they work at 3200 Mhz and 1.2v and they individually test them at higher frequencies and higher voltages and looser timings.

 

So out of 100k tiny chips, maybe 10k chips can function at 4600 Mhz but higher voltage (like 1.45v for example) and looser timings, so they make a stick out of 8-16 such chips and put in the stick a XMP profile (a list of parameters) that the bios can read and apply. 

As required for most compatibility, the sticks will still have standard profiles stored in them, for standard frequencies like 2666 Mhz, 3200 Mhz, 3600 Mhz and also with tighter timings.

If the motherboard knows it's not designed well enough to support 4600 Mhz sticks, the bios will look in the list of profiles and pick the next most suitable. If nothing is suitable, the bios will pick a profile that's hardcoded within the bios, for a standard frequency like 2133 Mhz or 2400 Mhz, and you'd have to force a  profile manually.

This is great, thanks for spending your hard-earned finger strength to type this. I'm writing this all down in a doc btw so know that you have just gained +1 respect 

[setsakara]

guys I started a new thread so lets go there instead