I always go for the biggest sized RAM sticks.
When I upgrade for 2024, I’ll pick a motherboard with 4 RAM slots and start with 32GB x 1.
Then 64, then 96 and finally 128.
Generally Windows has always been faster with more RAM and disabling virtual memory on disk or fixing it a low value.
With extra RAM you don’t need VM.
The RAM speed that you can run will depend on:
In my case my Z790 motherboard and Gskill 7200 MT/s memory
(4 sticks of 16 GB), will run Windows and apps (Browser, this Forum,
Word, Excel, Notepad, Task Manager) at 7200.
But FS2020 will not and runs at 6400 MT/s or lower.
And that is with an i5-13600K or i7-14700K.
The motherboard, Z790 AORUS ELITE AX, is spec’d at 7200 MT/s
and the memory at 7200 MT/s.
Note that Gigabyte spec’s this motherboard for 7200 MT/s capable.
This means that this motherboard successfully passed their test for running this memory at 7200 MT/s.
But:
My motherboard may be different. Might have a flaw.
Also, other than setting my BIOS to the XMS Profile,
I have no idea of what options were set in the BIOS for the memory
and the motherboard that they used to get 7200 MT/s.
My memory may have a flaw.
My CPU may have a flaw.
I was under the impression Arrow Lake would allow 4 x 64GB DDR5 for 256GB total.
Edit:
My memory is on the QVL at 7200 MT/s.
But the Arrow Lake CPU spec stated that max frequency
for the CPU is 6400 MT/s.
Intel® Core™ Ultra Desktop Processors (Series 2)
Maximum Memory Speed (MT/s) = DDR5-6400
Memory Support: Maximum memory speeds are associated with 1 DIMM per Channel (1DPC) configurations.
Additional DIMM loading on any channel may impact maximum memory speed. Up to DDR5-6400 MT/s 1DPC CUDIMM 1Rx8, 1Rx16, 2Rx8.
Maximum memory capacity is achievable with 2DPC configurations. For additional 2DPC configuration details, refer to the Arrow Lake-S and Arrow Lake-HX Processor External Design Specification (EDS), Doc ID 729037.
So, I don’t understand.
Edit:
Summary trying to understand this:
Z890 AORUS ELITE WIFI7
4 DIMM Sockets
256 GB max with 4 48 GB DIMMs
128 GB max with 4 32 GB DIMMs
64 GB max with 4 16 GB DIMMs
Support for 9200 MT/s
MB QVL - Fastest Gskill Max Memory Speed
16GB - Gskill, 8000 MT/s, 1Rx8, Hynix, 38-48-48-128, 1.45v
32GB - Gskill, 6800 MT/s, 2Rx8, Hynix, 34-45-45-108, 1.4v
48GB - Gskill, 6800 MT/s, 2Rx8, Hynix, 34-46-46-108, 1.35v
Arrow Lake CPU
Intel® Core™ Ultra Desktop Processors (Series 2)
Maximum Memory Speed (MT/s) = DDR5-6400
Memory Support: Maximum memory speeds are associated with 1 DIMM per Channel (1DPC) configurations.
What is the correct answer?
OK - still a decent amount more than the 128GB we got with the old chipsets, but not near the theoretical 512GB the DDR5 standard supports.
I plan for AM4 and Ryzen 7 5700X3D
If AM5 systems drop in price I’ll consider them, but I have to update my 1080GTI at some point.
Igabyte X870 motherboards support 256gb of RAM (both intel and amd cpu versions).
By the end of the decade we’ll have motherboards with a half terabyte of ddr6 system ram. Maybe by then I’ll need to upgrade …
I have 7950X3D with 64GB(2X32GB)CL30. In my experience, I did notice a smoother experience going from 32GB CL30 6000 to 64GB CL30 6000. I’m running Expo II with no issues on the 64GB.
Thank you!
Big amounts of RAM start to cause power issues.
Our genomics servers at work take either 3TB of normal RAM or can handle 6TB of super expensive low power RAM.
You do need VM in Windows - regardless of how much physical RAM you have.
Edit: best to let the system manage the VM size – see attached screenshot image:
Interesting info for sure, but I’m not sure why you are telling me this in the context of my post.
This topic is not really related to your consideration of changing CPU. However, since you’ve already asked, I’ll give you some insight: just because Intel recommends DDR5 6400 doesn’t mean it won’t work with for example DDR5 7200 XMP. Intel essentially guarantees compatibility with DDR5 6400 and motherboard manufacturers confirm that newer processors (Arrow Lake) also work with 7200 RAM adding that it is considered overclocked (OC/XMP).
If I’m not mistaken you currently have an i9 13900K that works with DDR5 7200. For this CPU Intel guarantees compatibility with DDR5 5600 but you have 7200 and it’s working fine for you. The same should apply to the newer processors so don’t sell your RAM 
“Big amounts” is relative. And ecc ram is of course more expensive, both for the chips and motherboard.
A decade ago 128gb of ram would have been unheard of in a home machine. I have 2 pcs with 128gb.
A 1000 watt power supply would have been serious overkill. Same.
20 tb would have been ginormous. Now you can get single drives with more than that.
256gb - at least - for my next build, just because.
It’s not about stability here but about memory speed and this applies to both Intel and AMD CPUs, not just AMD as someone suggested earlier. Four memory sticks might not work correctly when we enable Intel XMP or AMD EXPO/A-XMP profile. However, you just need to manually adjust (lower) their speed and there shouldn’t be any issue.
Intel is more stable than AMD with 4 sticks indeed, but what I’ve said above still holds true for Intel. Intel is more stable with 2 than 4. It’s easier to get better timmings, clocks using less voltage with 2 sticks. Most overclockers use two sticks because of that. But yeah, AMD is a lot worse on that aspect when compared to Intel.
Yeah, but Intel is more stable than AMD, Intel works better with 4 sticks, Intel can reach higher clocks etc. But still, 2 sticks will always be more stable than 4, doesn’t matter the platform.
One thing I like about my machines here is I don’t have to worry about 2 sticks -v- 4 sticks , I can put 12 of them if I want with no problems, aside from being slower to boot up given the RAM is all checked before the chime and loading the OS.
On one of my older machines I’ve had a one RAM chip fail, but still had 96GB. I just had to drop back from 8 to 6 chips, because it won’t work with 7 out of 8 and they have to be arranged in a particular order in the machine if you aren’t using all the slots.
That was my fault for buying that particular brand of RAM, will stick with Hynix now. Still was 6x16GB though, just not the full 128GB.
Problems with 4 sticks shouldn’t be at all common. If they were, every decent mobo out there wouldn’t be coming with slots for them.
I’ve used 4 a number of times and never had an issue. Of course the more you have of anything, you will be raising the chance of a problem, but it’s pretty insignificant imo. I do have one system with 3 sticks because 1 went bad after a few years. It’s been running fine on 3 for… 7 or 8 yrs now I think.
It’s a known issue for AM5 - 670E chipset
Running RAM not in dual channel mode is a known performance reduction in the 15% (ish) range
