Ddr5 and safe voltages/linpack residuals question?

[glenntidbur156f02e4]

Just wondering if there's a kind of definitive guide somewhere as to what are considered safe voltages for all settings in the bios.

I know that values turn red in bios when they're above recommended values, but in my system for example (pro z690-a Wi-Fi ddr5, 12700k, g.skill 6400cl32 2x16gb kit) shows the rated dram voltage of 1.4V in red..... but presumably, 1.4V is safe to run?

I've watched quite a few buildzoid vids on youtube, and done some reading on various forums, but I'm still a bit confused about what is safe for daily use? I have seen his video about safe/brave voltages, but didn't know if this is still up to date and accurate with the latest bios/ram updates?

I'm mainly asking because I literally JUST found out that in msi bios "CPU VDDQ" is the "transmitter" voltage that's talked about in a lot of overclocking videos/forums....and by default, with xmp enabled, the bios only sets this to 1.35V, even though the other DRAM VDD and DRAM VDDQ voltages are 1.4.....and the system won't reliable post with VDDQ @ 1.35V at anything above 5800Mhz.....but if I bump it up to match, 1.4V suddenly things boot every time, no issues getting the machine to post, no matter how many times I reboot, enter bios, restart, shutdown or anything.....it just reliably posts every time even at the rated 6400mhz. (I haven't even attempted to go beyond that yet lol)

Is this voltage SAFE to use daily though?

I guess my questions are: -

What are considered max SAFE voltages for alder lake DDR5 systems for: -

SA voltage
CPU VDDQ
CPU VDD2
CPU AUX (although default hasn't given me any issues)
DRAM VDD
DRAM VDDQ

and as a secondary...when testing system stability with linpack, I've seen mixed answers even from buildzoid regarding whether or not the residuals have to match. I've seen some videos where he says, as soon as he sees that the residuals don't match, he knows it's not stable, but there have been other parts where he says he was wrong about residuals having to match on modern intel systems and just look for the "pass"?

I mean, even at stock 4800CL40, my current PC blows my old on out of the water.... but I'm always on a quest to get the most out of my system.

My CPU I can't really push past stock, in fact I undervolted by around .120V in order to keep temps below 80 even in stress testing (in gaming they're MAX around 65, usually hovering around 50). (Although if anyone else can point me in the direction of how to maintain such low temps without losing any performance, I'm all ears.... I tried lite load options, and they did reduce temp, but absolutely killed performance, which undervolting didn't). As soon as I start trying to do an ALL-CORE OC, or raise the turbo even by +1, temps go up to 100 and beyond, and I'm not really comfy with that, even though it's only in stress testing where it reaches those temps..... I like to keep things at most 85, preferably below 80. SO yeah, CPU stock frequencies, undervolted seems like the best balance for this?

My GPU (gigabyte 3080ti gaming OC 12GB) I have a custom curve that raises the lower end a fair amount but levels off toward the higher end to maintain stock frequency the higher up the voltage curve you go, and I've found this to be extremely stable while giving a slight performance boost. I spent a long time trying to undervolt to a set point, or straight up OC by a set amount, but it was never ever stable, so I think that on MY gpu raising the low end and raising by less and less the higher up the voltage curve I go, seems to work, and is the best compromise?

So, the RAM is really the final piece of the puzzle. I was running 5800CL30 with tightened sub timings (thanks buildzoid for your easy and fast Hynix timings vid), but I'm still really confused about what is safe to run, and if you can still consider things stable if the linpack residuals don't match? As linpack is the quickest of all the stress tests, I don't want to spend hours running hci memtest or kharu or memtest86, if nonmatching residuals in linpack is a quick and easy indicator that it's NOT stable?

Really appreciate any input and understanding of how things work and what exactly I should be looking for when testing things?

 

[RemusM]

What are considered max SAFE voltages for alder lake DDR5 systems for: -

SA voltage
CPU VDDQ
CPU VDD2
CPU AUX (although default hasn't given me any issues)
DRAM VDD
DRAM VDDQ

First of all, overclocking and overvolting are faulty activities.
That being said, you'll get a bunch of different answers here from overclockers and "enthusiasts".
In other words, when overclocking and overvolting you're gambling and the result is not the same for all.
What's safe for me, might not be safe for others ...
Long story short (I have to go), if you need my answer here: 1.4V for SA and 1.35V for the rest.
cheers

 

[glenntidbur156f02e4]

That's true. Thanks for the info, appreciated. I'll probably just either stick with my 5800cl30 or just run at stock (4800cl40, but much lower voltages).

If I were to push things further though, anyone able to answer about the linpack residuals?

 

[doug.hogart153b02d9]

If I were to push things further though, anyone able to answer about the linpack residuals?

I am not an expert but this bugged me around a year ago so I researched a bit. There are articles about libraries not returning exact reproducible results unless you set some environment variable, something like MKL_CBWR = AVX2,STRICT mentioned at the bottom of Intel's https://www.intel.com/content/www/u...onditional-numerical-reproducibility-cnr.html

How to set environment variable is explained near the middle of the following of Microsoft's https://learn.microsoft.com/en-us/t...ent-results-mkl-computations-missing-variable, except they use the value AUTO instead of what I mention above so change that. I suppose you could try AUTO,STRICT.

 

[glenntidbur156f02e4]

Thank you.

 

[glenntidbur156f02e4]

Ok, it turns out that the answer is probably even simpler than all this.....I totally forgot that my pc is set up to start a whole bunch of background programs (mostly due you flight sim, but also things like afterburner to keep track of temps, razer to setup my mouse buttons etc).... turns out that, obviously, any stress testing or cpu/ram benchmarks really don't like having a whole bunch of other programs running in the background..... and it has a profound affect on the residuals in linpack.

Im just running a quick test now, but booted in safe mode, and even at 6400cl32 (the rated speed of the kit), 10 passes in so far, all residuals match, all times are 42.xxx s, all gflops are 676.xxxx and all pass.

So im gonna let this run of 40 finish, then boot back into normal windows/not safe mode, repeat the test but with all the usual startup programs closed down. If they still all pass and mostly match residuals, then I can move on to memtest hci and kharu.

 

[citay]

Don't worry too much about the residuals on 12th/13th gen, you can get non-matching ones there, i think it has to do with the concept of P-cores and E-cores, see here.
On 11th gen and older, non-matching residuals would be a red flag, but that concept isn't so clear anymore on Alder Lake and Rocket Lake.
In safe mode, it's safe to say that some of the advanced CPU features don't come into play, therefore you get matching residuals.

About the voltages, buildzoid's channel is appropriately named "Actually Hardcore Overclocking". Sometimes he goes for a high overclock with voltages that i would never use on my personal system, so keep that in mind. Neither he nor MSI would be the authority on "safe" voltages. MSI have bipolar disorder: With XMP enabled, they tend to raise the IMC-related voltages sky-high, while simultaneously having a low threshold for the red=dangerous color when you raise certain voltages yourself.

I have no experience with DDR5 myself, but with DDR4, 1.4V was already elevated from the standard XMP voltage of many kits (1.35V) which in itself was elevated from the JEDEC voltage of 1.2V. So with DDR5 the nominal operating voltage / JEDEC is 1.1V, meaning 1.4V would be more on the extreme side. However, if the kit is rated for it, then it's safe.

 

[glenntidbur156f02e4]

True. Anyway, I was getting matching residuals upto around 15 passes in normal windows mode (not safe mode), but after 16 passes this time I got bsod lol.

So I think just back to stock. Games run fine at stock, and like I said, still blows my old system out of the water.

I think the annoying thing is that I forked out for fast ram when I decided to upgrade to 32gb.... thinking... well, if I'm upgrading, I may as well get the best performing ram that I can....

And the funny thing is, at the time I decided to upgrade to 32gb, it was for flight sim, as previously I was told that msfs made good use of ram, so the more the better and 32gb was considered a good amount.... but they then released an "update" which limited the amount of ram that the sim could use to around 8gb..... because.... reasons?

Haha.

Anyways, thanks for all the info.