CPU Choice for 128GB DDR5

[Mr Technician]

I am building a workstation that will also be used for gaming and am trying to target the highest memory frequency I can while still running 128GB of DDR5. It seems the best option for this is the 13900k with even the Microcenter advertising touting "128GB DDR5-5600 Memory Supported." I have seen a handful of videos of people running even 6000 MT/s on a 13900k, but I understand my mileage may vary. The 7950x seems to be in a much worse position for memory support requiring much lower speeds.

 

While I do prefer AMD's more power efficient approach, it also looks like the 13900k has better idle power consumption, which is important as this machine will be used to view VDI for my day job 40 hours a week (practically 0 CPU usage). The bottom line seems to be that for a part workstation, part gaming, and part VDI machine, Intel is the better choice.

 

Any thoughts?

 

Edit: If I can't get 128GB to run, I may return it and fall back to 96GB with these 48GB DIMMs: https://www.newegg.com/g-skill-96gb/p/N82E16820374465

For 128GB, this would be my choice x2: https://www.newegg.com/g-skill-64gb-288-pin-ddr5-sdram/p/N82E16820374383

[Shimejii]

What use case do you have that benefits from that much ram? Look into what your programs benefit from exactly.

 

You wont be able to run it beyond 4800mhz more then likely.  Microcenter advertising is generally untested, they trust what they got told by the sellers and dont actually test it themselves. Its been tested by level 1 techs and a few other techtubers, you wont get fast speed with 4x32 dimms. 4x24 dimms wont go well as well, you could try 2x48 dimms, but again i dont expect the speeds to be super fast and have the vest stability.

 

Workstation requires Rock solid stability over speed.

 

[Mr Technician]

18 minutes ago, Shimejii said:

What use case do you have that benefits from that much ram? Look into what your programs benefit from exactly.

Davinci Resolve (4k, maybe 6k if I start using ProRes Raw) and Blender. I also develop software and want to dip into Unreal engine. I have a bad habit of running every application at once. Oh, did I mention I want to be able to run a VM or two?

 

20 minutes ago, Shimejii said:

You wont be able to run it beyond 4800mhz more then likely. 

For which CPU?

[Shimejii]

8 minutes ago, Mr Technician said:

Davinci Resolve (4k, maybe 6k if I start using ProRes Raw) and Blender. I also develop software and want to dip into Unreal engine. I have a bad habit of running every application at once. Oh, did I mention I want to be able to run a VM or two?

 

For which CPU?

1st part, dont ever do that. Learn to close the damn programs when you arent using them. No amount of RAM will alleviate the issues by doing this.

 

Video editing and such yes its understandable, if you were actually making any money doing this. If you are still doing that as a hobby without making any money, overspending is wasteful and better spent elsewhere. 64 GB of ram will be more then adequete.

 

VMS i dont see peoples obsession with having VMS, unless you are actually doing things that require a VM, is there anything that you actually do that benefits from having one? Its something you will do rarely, not something you should prioritize.

 

For the question of Which CPU? Intel here is the much better choice, but even then it will get you pretty much no where. Jayz2Cents Editor Phil went with 128 GB of ram and they could not get it to go beyond 4800 mhz without instability, Level1Techs as mentioned before tested this out as well and also came to a similar conclusion, 128 GB of ram just isnt all that stable beyond the Minimum spec. 

[RONOTHAN##]

8 minutes ago, Mr Technician said:

For which CPU?

13900K. Fastest I've seen with quad rank is 5200, and with 13th gen chips especially running near the limit can give you some really weird results (1 error every 12 hours in memory stress tests). 4800 would be the fastest I'd be willing to run for a workstation with 128GB of RAM on 13th gen, and there is a non-zero chance I'd just underclock it to 4400MT/s or lower just to be safe. 

 

4x24 or 2x48GB would go a bit better, though 6800MT/s with dual rank is still much higher than what I'd reasonably expect to work with no effort. The 6400 CL32 version of that memory kit would have a significantly higher chance of just working. 

[igormp]

AFAIK, the 48GB dimms are able to achieve better clock speeds.

3 minutes ago, Mr Technician said:

I have seen a handful of videos of people running even 6000 MT/s on a 13900k

With 128gb? Where? All I've seen was people reaching at most 4600~4800MHz with tons of luck.

 

From what I've seen, you can actually achieve higher speeds with AMD, some folks managed to get past 5000MHz with both 128 and 192gb. These threads in the neighbor forum may be relevant for you:

https://forum.level1techs.com/t/7950x-i-want-4x32gb-unless-it-sucks-does-it-suck/189825

https://forum.level1techs.com/t/ddr5-4-dimms-on-am5-whats-working-whats-not/197153/

 

As a fellow 128gb ram user, I'm honestly kinda disappointed at both the density and speeds achievable on DDR5 platforms and the issues that come with them. 128gb 3200 MHz on my 5950x was just plain plug and play.

[Mr Technician]

38 minutes ago, Shimejii said:

64 GB of ram will be more then adequete.

I quite respectfully disagree on this one. Video editing applications can absolutely devour memory when dealing with ProRes.

 

13 minutes ago, igormp said:

With 128gb? Where? All I've seen was people reaching at most 4600~4800MHz with tons of luck.

This is one I had found but in retrospect, take it with a grain of salt because he is using the task manager to verify the speed: 

 

 

41 minutes ago, Shimejii said:

Jayz2Cents Editor Phil went with 128 GB of ram and they could not get it to go beyond 4800 mhz without instability

I stand corrected on that one, I watched that but forgot about it. 

 

I will look more in depth at the links tomorrow but I might end up going with 2 x 48 GB instead to save the hassle.

[Shimejii]

8 minutes ago, Mr Technician said:

I quite respectfully disagree on this one. Video editing applications can absolutely devour memory when dealing with ProRes.

 

 

Again, you can make it WORK, its all about balance. People who actually edit for a living yes it makes sense to do this. Are you actually dealing with the amount of Footage they do? Are you a video editor at one of these places where you are actually utilizing it? Remember they are, and if you are just doing this for a hobby, it really does not make sense to do it. If you are only editing a few 100 GB of footage every now and again you wont run out of ram with 64 GB, if you are dealing with it a LOT more then just every once in a while sure i could see it being worthwhile to do 128. 

 

Just because they do it does not mean you should, often times they do not pay for it they get sent it and do sponsor reads, advertising etc. Gotta get the best for what works for you and what you will actually use, not just what they use. If you feel as if you will get benefits from it from your own personal testing, then by all means go for it, but please do test to make sure because 128 GB is going to take a bit of tuning to get it properly stable.

[RONOTHAN##]

35 minutes ago, Mr Technician said:

This is one I had found but in retrospect, take it with a grain of salt because he is using the task manager to verify the speed: 

Yeah, plus his stability testing is borderline non-existent. First off, XTU barely counts as a stress test, both for memory and CPU. It just doesn't actually pick up on errors until the point where Windows is already randomly blue screening in my experience. Second, he only recommends stress testing for an hour, which with Intel DDR5 just isn't long enough (I would argue it isn't enough on AMD as well, but there at least the errors you run into after an hour are either FCLK if you're pushing that or temperature errors, not CPU instability like you get on Intel). Most of the errors I've gotten when going for high frequency have been after 4 hours or longer, and it's usually only 1-2 at a time. Those 1-2 errors after 4 hours are enough to corrupt an OS or cause a random system/software crash at the worst possible time, not recommended for a daily system. My guess is even at 5600 his system wouldn't survive something like Y-Cruncher VST (generally considered the hardest stress test to pass when going for high frequency on 13th gen) for longer than 5 minutes. 

 

The Intel memory controller is more capable than the AMD memory controller, but at least the AMD memory controller is consistent and either works or it doesn't, no random single errors after 4+ hours of stress testing. 

[igormp]

1 hour ago, Mr Technician said:

This is one I had found but in retrospect, take it with a grain of salt because he is using the task manager to verify the speed: 

 

 

I'd take this with a heavy grain of salt. He only managed 5600MHz and didn't show any proper stability tests going. Even so, he did mention that 6000MHz wouldn't even boot.

 

15 minutes ago, RONOTHAN## said:

The Intel memory controller is more capable than the AMD memory controller

For 1DPC it does seem to be the case, however for 2DPC, specially when going for high density dimms, intel's IMC seems to just give up completely. 12th gen on DDR5 couldn't even go past 4000MHz on 128GB, usually stopping at 3600MHz, which is basically DDR4 speeds that everyone is almost guaranteed to achieve.

17 minutes ago, RONOTHAN## said:

but at least the AMD memory controller is consistent and either works or it doesn't, no random single errors after 4+ hours of stress testing. 

Look at the links I mentioned before, when dealing with 128/192GB it is usual to be able to boot at 5000MHz+ and only get random errors after long hours of testing.

[Mr Technician]

20 hours ago, Shimejii said:

but please do test to make sure because 128 GB is going to take a bit of tuning to get it properly stable.

I've given this some thought today and I think I agree with you on the 128GB part, so I will scale back to "only" 96GB.

 

19 hours ago, igormp said:

I'd take this with a heavy grain of salt. He only managed 5600MHz and didn't show any proper stability tests going. Even so, he did mention that 6000MHz wouldn't even boot.

Ok, good points.

 

20 hours ago, igormp said:

Look at the links I mentioned before, when dealing with 128/192GB it is usual to be able to boot at 5000MHz+ and only get random errors after long hours of testing.

So again this reinforces that I should get 2X 48GB and not need to deal with it this issue. I might see if I can 3D print a couple of dummy sticks so I don't have an awkward gap - assuming I don't get RGB RAM, that is.