DDR5 RAM questions

[XMD7007]

I'm going to assemble a new PC soon, preferably still this year, either for Intel 13000 series or for AMD 7000 series CPUs. So I looked into what's available right now in terms of RAM, and as it seems there are no high end max. capacity 4 x 32 GB DDR5 kits available.

The question whether it makes sense aside, is there any technical reason not to buy two 2 x 32 GB DDR5-6000 kits to get to 128 GB in total?

Another question is (if I decide to go ITX), why do ITX mainboards limit the RAM to 64 GB? I thought DDR5 modules will exceed 32 GB per module and the memory controller of the CPU, or wherever it sits, allows for 128 GB in total. So theoretically we could have 2 x 64 GB in future on ITX Mainboards, but this seems to be excluded according to ITX Mainboard specifications.

[Stickiler]

I'm going to assemble a new PC soon, preferably still this year, either for Intel 13000 series or for AMD 7000 series CPUs. So I looked into what's available right now in terms of RAM, and as it seems there are no high end max. capacity 4 x 32 GB DDR5 kits available.

The question whether it makes sense aside, is there any technical reason not to buy two 2 x 32 GB DDR5-6000 kits to get to 128 GB in total?

Another question is (if I decide to go ITX), why do ITX mainboards limit the RAM to 64 GB? I thought DDR5 modules will exceed 32 GB per module and the memory controller of the CPU, or wherever it sits, allows for 128 GB in total. So theoretically we could have 2 x 64 GB in future on ITX Mainboards, but this seems to be excluded according to ITX Mainboard specifications.

Which motherboards are you looking at? In general, the amount of RAM supported is based on the CPU, the available RAM slots, and the amount of RAM available per stick for that RAM type.

[XMD7007]

I was looking mainly at Z790 ASUS ROG mainboards, ITX and ATX.

ITX: ASUS ROG STRIX Z790-I GAMING WIFI
According to their tech specs on their website: 2 x DIMM, Max. 64GB, DDR5

Why do Z790 ITX mainboards exclude the usage of 2x64 GB DDR5 RAM modules in their specifications? I know that these modules aren't available right now, but that's not a reason to exclude them right now in the tech specs of the mainboard. So there must be some other limitation I'm not aware of. The CPU allows 128 GB and the DDR5 modules will also allow for 2x64 GB sometime soon.

[chazus]

Why do Z790 ITX mainboards exclude the usage of 2x64 GB DDR5 RAM modules in their specifications?

It's hard to develop support for something that doesn't exist yet. Single Rank 64gb DDR5 simply isn't manufactured yet, and there may be limitations involved. It's possible the board can be updated later with a BIOS update that supports it, but right now... What does that matter? You cannot buy it so it's not an option. 2x 32gb is what you're going to get on anything with 2 slots.

[Linkedblade]

I was looking mainly at Z790 ASUS ROG mainboards, ITX and ATX.

ITX: ASUS ROG STRIX Z790-I GAMING WIFI
According to their tech specs on their website: 2 x DIMM, Max. 64GB, DDR5

Why do Z790 ITX mainboards exclude the usage of 2x64 GB DDR5 RAM modules in their specifications? I know that these modules aren't available right now, but that's not a reason to exclude them right now in the tech specs of the mainboard. So there must be some other limitation I'm not aware of. The CPU allows 128 GB and the DDR5 modules will also allow for 2x64 GB sometime soon.

You're limited on ITX boards to two dimm slots. That's the limiting factor. Intel 12th gen cpus are limited to 128 GB max by spec.

If you want 128 GB, 4x32 is the better option for price, if and when a 64 GB dimm comes to market. With that said 64GB ddr5 does exist on the server market, but nothing yet on the consumer side.

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Another question is (if I decide to go ITX), why do ITX mainboards limit the RAM to 64 GB? I thought DDR5 modules will exceed 32 GB per module and the memory controller of the CPU, or wherever it sits, allows for 128 GB in total. So theoretically we could have 2 x 64 GB in future on ITX Mainboards, but this seems to be excluded according to ITX Mainboard specifications.

Not sure if it's part of the spec by intel, or if they are using market availability like chazus said. The highest amount of ram on a single dimm, for now, is 32 GB. So, at best an ITX board can do 2x32.

[Ssateneth]

You will not get 6000 XMP speeds using 4 sticks. Current platforms may limit you to 4000MHz, 3600MHz, or less, using 4 ranks of memory in dual channel.

[Temp name]

You will not get 6000 XMP speeds using 4 sticks. Current platforms may limit you to 4000MHz, 3600MHz, or less, using 4 ranks of memory in dual channel.

I mean, that's like DDR4 speeds, and considering DDR5 spec is between 4800 and 7200 mhz, I'm pretty fucking sure you can get above 4000

[Ssateneth]

its the truth. good luck getting even past 5000 with quad rank dual channel.

[Temp name]

its the truth. good luck getting even past 5000 with quad rank dual channel.

But 4000 and 5000 are very different though

[rogoth]

its the truth. good luck getting even past 5000 with quad rank dual channel.

DDR5 doesn't go below 4800 MT/s, furthermore, there's no such thing as 'quad channel' on consumer grade personal use motherboards, it's dual channel x2, in order to run quad channel spec you need an enterprise grade motherboard and a CPU that supports quad channel, so please do us a favour and stop speaking utter bullshit and do some research before speaking again.

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As a previous mITX enthusiast for about 8 years, mITX isn't worth the compromises in 2022 with TDPs doubling. Unless there's a reason to go SFX, the compromise isn't worth it. If your overall thermal output is below 300W or so, then sure.

Its an unfortunate reality with 250W CPUs and +300W GPUs that its just not fun to build around anymore. I dont trust even the best SFX PSU to a newer gen card.

i don't think you can get a high enough wattage PSU for that form factor for any modern setup combo, you need to do a dual PSU setup in order to have enough power to run the system as per your noted restrictions.

[Temp name]

DDR5 doesn't go below 4800 MT/s, furthermore, there's no such thing as 'quad channel' on consumer grade personal use motherboards, it's dual channel x2, in order to run quad channel spec you need an enterprise grade motherboard and a CPU that supports quad channel, so please do us a favour and stop speaking utter bullshit and do some research before speaking again.

He's saying quad rank, dual channel, not quad channel. If you want to try and be a pedant, do it right

But honestly, with how new DDR5 is, the point is rather moot anyway, give it a year and we'll see memory go way beyond JEDEC spec like we did with DDR4

[rogoth]

He's saying quad rank, dual channel, not quad channel. If you want to try and be a pedant, do it right

But honestly, with how new DDR5 is, the point is rather moot anyway, give it a year and we'll see memory go way beyond JEDEC spec like we did with DDR4

yeah i re-read what was said, and even then it still doesn't change the fact that, that type of DIMM is enterprise grade exclusively, so my point stands regardless of which mode you want to use, because currently there is no consumer grade DD5 module with that type of memory config, as to your timetable, i doubt it will take that long before DD5 uptake is 'normalised', because of how much AMD is pushing it as an exclusive platform requirement, and the fact Intel has basically killed off it's 1700 socket platform and will be moving to a new one for their next chip release it's likely they will make that DDR5 exclusive like AMD has, and since Intel is desperate these days they are releasing CPU chips within a 12 month window to try and push quantity over quality.

[XMD7007]

Ok thanks, so most of my questions are answered in some way or another:

- There are currently no 64GB DDR5 sticks available, so no one can say whether 2 x 64GB on ITX will be a thing in the future or not, not even the manufacturers.
- Reaching 6000 MHz with 4x32GB sticks, which are specified to run @ 6000 MHz, might still be an issue. Though no word on this in the spec sheets of the RAM or the MB.

One questions remains: is there a difference between 2x2x32GB and 4x32GB RAM kits? Talking about the same type of RAM with same model number and same specifications. Are the ram sticks in a 4x32GB kit somehow selected and matched to each other so that it's not the same thing as buying two 64GB kits of the same RAM model?

[chazus]

One questions remains: is there a difference between 2x2x32GB and 4x32GB RAM kits? Talking about the same type of RAM with same model number and same specifications. Are the ram sticks in a 4x32GB kit somehow selected and matched to each other so that it's not the same thing as buying two 64GB kits of the same RAM model?

Outside of ranking and channels, there isn't a huge difference. "Matched" (as far as I'm aware) simply means that two sticks of ram are bundled together from (in theory) the same batches, meaning they will be as identical as you can get, and are often even next to eachother serial number-wise. This is effectively the best way to gaurantee that they are aligned in speed, performance, and compatibility. You could buy 2 2x32 kits and they will 99.9% be fine and compatible and without issue... But I'm sure someone at some time has bought a 2x32 or 2x16 kit, and a week later bought a second of the same SKU and the resulting shipment of parts has the same part number and look identical but... different batch, different silicon, slightly different performance.

TLDR either are fine it's really not a huge concern unless you're doing funny voltage/speed stuff.

[Kagthul]

Its an unfortunate reality with 250W CPUs and +300W GPUs that its just not fun to build around anymore. I dont trust even the best SFX PSU to a newer gen card.

As an mITX enthusiast, i dont get this.

There are 1000w SFX and SFX-L PSUs out there. Not that you need one that big anyway. Unless you're taking mITX-in-name-only cases like the Evolv ITX (which is really just a shortened mATX case, and also fits ATX PSUs) you aren't realistically putting a high-wattage CPU and a 4090 in any modern truly ITX chassis simply due to heat generation, and likely, in the case of the 4090... its simply not going to fit anyway. Most max out at 3 slots and 4090 AiB cards are going to be 3.5+ (i havent seen any true 3 slots yet).

But heat will be the major issue. There's simply no room in truly small ITX cases for enough cooling/rad space. If you tried to cram a 13900K and a 4090 Into an ITX rig, you'd have to run them bone-stock and undervolt them (you should undervolt them anyway, but that is neither here nor there) to not burn them up and throttle in any ITX case i can think of (there may be some that this isnt true, but i haven't. seen them).

If you want that in an ITX form factor you're going to have to go with something like the Evolv ITX or NZXT H210 (or hopefully a replacement with better airflow) in size, where you have room for a giant-ass GPU and a good 360mm radiator. And those larger ITX cases usually support ATX PSUs anyway.

Even then... 250W CPU, 400W GPU.... 50-70W for the rest of the system... with an 850 you've still got headroom. Not that either the CPU or GPU will pull those numbers 100% of the time anyway.

i don't think you can get a high enough wattage PSU for that form factor for any modern setup combo, you need to do a dual PSU setup in order to have enough power to run the system as per your noted restrictions.

.... whut? the extreme OUTSIDE of the "modern setup curve" is a 13900K with a 4090. That can be run on an 850W PSU without issue, unless you are for some reason trying to do massive overclocks (which aren't going to gain you much in terms of performance, particularly for gaming) and running them totally maxed out 100% of the time.

Seriously, people have GOT to stop with this PSU panic shit. "ZOMG you need AT LEAST A THOUSAND WATTS for a modern system".

No the fuck you dont.

[Atrea]

Just out of curiosity, what practical application do you have for 128GB of RAM?

[chazus]

Seriously, people have GOT to stop with this PSU panic shit. "ZOMG you need AT LEAST A THOUSAND WATTS for a modern system".

No the fuck you dont.

Meanwhile I'm all excited about the 1080p gaming potential of some of the new <100w CPUs

[rogoth]

As an mITX enthusiast, i dont get this.

There are 1000w SFX and SFX-L PSUs out there. Not that you need one that big anyway. Unless you're taking mITX-in-name-only cases like the Evolv ITX (which is really just a shortened mATX case, and also fits ATX PSUs) you aren't realistically putting a high-wattage CPU and a 4090 in any modern truly ITX chassis simply due to heat generation, and likely, in the case of the 4090... its simply not going to fit anyway. Most max out at 3 slots and 4090 AiB cards are going to be 3.5+ (i havent seen any true 3 slots yet).

But heat will be the major issue. There's simply no room in truly small ITX cases for enough cooling/rad space. If you tried to cram a 13900K and a 4090 Into an ITX rig, you'd have to run them bone-stock and undervolt them (you should undervolt them anyway, but that is neither here nor there) to not burn them up and throttle in any ITX case i can think of (there may be some that this isnt true, but i haven't. seen them).

If you want that in an ITX form factor you're going to have to go with something like the Evolv ITX or NZXT H210 (or hopefully a replacement with better airflow) in size, where you have room for a giant-ass GPU and a good 360mm radiator. And those larger ITX cases usually support ATX PSUs anyway.

Even then... 250W CPU, 400W GPU.... 50-70W for the rest of the system... with an 850 you've still got headroom. Not that either the CPU or GPU will pull those numbers 100% of the time anyway.



.... whut? the extreme OUTSIDE of the "modern setup curve" is a 13900K with a 4090. That can be run on an 850W PSU without issue, unless you are for some reason trying to do massive overclocks (which aren't going to gain you much in terms of performance, particularly for gaming) and running them totally maxed out 100% of the time.

Seriously, people have GOT to stop with this PSU panic shit. "ZOMG you need AT LEAST A THOUSAND WATTS for a modern system".

No the fuck you dont.

the FE 4090 is exactly 3 slots, and there's a couple of AIB cards that are also exactly 3 slots, the only ones that are bigger than this are the flagship cards from the likes of ASUS/MSI/GIGABYTE which are 3.15-3.25 slot cards with only one revealed card so far being more than 3.5 slots wide.

no, it can't, there's only 3 4090 cards that have a MINIMUM required PSU of 850 watts, and those are required minimum using the new 3.0 standard, not currently available as of writing this comment, everything else recommends a 1000W PSU for ANY 4090 based setup regardless of CPU being used, and it's highly likely that out of the box the 13900k will draw 300W on its own WITHOUT ANY OVERCLOCKING, because it's well established Intel has fuck all in terms of efficiency with their chips, the 12900k is already pulling 250+W under load which is way above the TDP claimed by Intel prior to their release, and it only gets worse when you factor in their KS sku.

as a result of the above, there's not a single SFX PSU capable of meeting these demands currently in existence, and the only ones that could would need to break the form factor to fit the sheer size of these GPUs it's no longer within the definition of the type, hence my comment.

if the makers of these products are stating you do, then you do, some rando fucking neckbeard on the internet isn't gonna change that fact just because in the past it didn't work that way, times have changed, technology has shifted into being high power and pushing limits, gone are the days of trying to be conservative with power draw and pushing performance metrics with other means, now it's all about going full throttle at all costs, and i'm going to trust the words of these manufacturers over both my own extensive past experience and people bitching online than not because i have seen what's happened when people have gone against modern guidelines and it's not a fun time, so you keep living in the past with your imagined requirements, see how that works out in practice, i pray nobody ends up out of pocket as a result of listening to bad advice.

[Ssateneth]

i never said quad channel. i said quad RANK. if you dont know what a memory rank is, look it up, otherwise, don't talk about things you have no clue about.

[rogoth]

i never said quad channel. i said quad RANK. if you dont know what a memory rank is, look it up, otherwise, don't talk about things you have no clue about.

i know what it is, i was half asleep at the time i replied initially and went back and reread what was written after someone else pointed it out, furthermore, DDR5 modules do not come in that memory config for consumer use, so regardless of my incorrect initial statement, the conclusion was accurate, if you want quad rank dimms you need an enterprise grade system and nobody is buying that kind of hardware for a personal rig at home, not to mention i don't even know if you can buy it as a personal consumer without a business license, methodology faulty, conclusion correct, you still haven't made a valid point yet.