Cannot enable 4000MHz CL16 on Z790

[yoadknux]

Just an update over time. 4000MHz 16-16-16 1.45V in Gear 1 with manual timings was Karhu and Memtest stable, but fails Prime95 large FFT quickly and consistently. On the other hand 3600 14-14-14 is Prime stable, so I just stayed with it. I guess maybe I could try 3800 14-16-16 at 1.5V but RAM oc is such a tedious process.

 

[EarthDog]

but fails Prime95 large FFT quickly and consistently.

So do most things. If there's one test I never run, it's that one, lol. There comes a time when you need to use your PC as you normally would to see if it's stable. 90% of the time that failed, I was stable doing daily activity... unless you're running those stress test-like loads or your work needs that stability, it's can be a waste of time to test that thoroughly.

but RAM oc is such a tedious process.

I gave up years ago. The amount of effort versus returns was never worth it (to me) outside of the benchmarking realm. It's easier to buy the speed you need with XMP and go from there (though more costly). Looks like you made it though!!!

 

[magellan]

@Woomack and ED
Is the OP's issue w/his RAM sticks, his motherboard or CPU? It's a Raptorlake, the last DDR4 capable CPU from Intel and it can't get 4000Mhz.? That doesn't make any sense considering there are 8700k's that can get to 4000Mhz. and more.

For the original OP (yoadknux), you might consider looking for other people who own Aorus Elite Z790 motherboards and look at their BIOS settings for RAM sticks of similar density/size and speed and see if you can get a template of their settings. Alternatively, if Gigabyte has forums dedicated to their motherboards you could look there for more specific help w/your model+make of motherboard.

Just for chuckles, what are your IOL's/RTL's set at? Can you set RTL init or IOL init?

 

[EarthDog]

@Woomack and ED
Is the OP's issue w/his RAM sticks, his motherboard or CPU?

See post #7.

 

[yoadknux]

@Woomack and ED
Is the OP's issue w/his RAM sticks, his motherboard or CPU? It's a Raptorlake, the last DDR4 capable CPU from Intel and it can't get 4000Mhz.? That doesn't make any sense considering there are 8700k's that can get to 4000Mhz. and more.

For the original OP (yoadknux), you might consider looking for other people who own Aorus Elite Z790 motherboards and look at their BIOS settings for RAM sticks of similar density/size and speed and see if you can get a template of their settings. Alternatively, if Gigabyte has forums dedicated to their motherboards you could look there for more specific help w/your model+make of motherboard.

Just for chuckles, what are your IOL's/RTL's set at? Can you set RTL init or IOL init?

I spent a lot of time on this and wrote a "journal" in this post so I'll summarize it for you:

1. Woomack was on point with this, Z690+Z790 are just not DDR4-optimized platforms. Buildzoid also once said "XMP 4000 just generally doesn't work on all 12th gen CPUs. Anything rated over 3600 is matter of luck or skill."
2. I've found a lot of threads with Aorus Z690 and Z790 owners that had issues with XMP. Both with DDR4 and DDR5.
3. My conclusion is that it's a BIOS problem. The main issue was that default XMP set 4000 16-16-16 with Command Rate 1T. That's not gonna boot on almost anything. Even 4000 16-16-16 with 2T probably needs manual tweaking of VCCSA and RAM voltage.
4. My board can do 4000MHz. It's just a question of timings. My older Neo kit runs 100% XMP stable at 4000C18, no tweaking. This new Royal kit runs 4000C16 with tweaking, it just fails a particular stress test and passes the others. I've found stability on that particular test with 3600C14 and 3800C15.
5. I also think G-Skill released an overly-binned kit: 1.4V is low for 2x16 4000C16. I had more stability with 1.45V. For example, the kit in your signature (4222C17) is rated for 1.5V - I never went that high. Patriot kits are also 1.45V+ at these timings.
6. All my tests were under Gear 1, meaning memory frequency = controller frequency. Supposedly Gear 2 allows higher bandwidth at the cost of latency and I didn't want that. I guess speeds like 4200 would be achievable there. There's also a chance that my 13600k has worse IMC than 13700k/13900k.

So it's really the motherboard, but this RAM is also very picky

 

[yoadknux]

So do most things. If there's one test I never run, it's that one, lol. There comes a time when you need to use your PC as you normally would to see if it's stable. 90% of the time that failed, I was stable doing daily activity... unless you're running those stress test-like loads or your work needs that stability, it's can be a waste of time to test that thoroughly.


I gave up years ago. The amount of effort versus returns was never worth it (to me) outside of the benchmarking realm. It's easier to buy the speed you need with XMP and go from there (though more costly). Looks like you made it though!!!

I really agree with you on that. Honestly I wanted things to be exactly like you wrote: buy fast memory with XMP, enable, don't touch. But it just didn't work for me. I had to manual tweak otherwise it would be an expensive kit that sits unused in some drawer. And when you start doing it, you may as well do it right, that's why I kept posting updates. In the end it turned out fine.

 

[EarthDog]

I had to manual tweak otherwise it would be an expensive kit that sits unused in some drawer.

That's an interesting way to think about it... if you run the sticks rated speed and don't overclock them, they're as good as being sitting unused in a drawer?????!!

 

[yoadknux]

That's an interesting way to think about it... if you run the sticks rated speed and don't overclock them, they're as good as being sitting unused in a drawer?????!!

If I can't enable XMP with a kit, then yeah, either I resolve the issue with manual timing (like I did) or it goes into some box. A 4000C16 kit without XMP defaults at 2133C15? That's useless.

 

[EarthDog]

If I can't enable XMP with a kit, then yeah, either I resolve the issue with manual timing (like I did) or it goes into some box. A 4000C16 kit without XMP defaults at 2133C15? That's useless.

Oh yeah, forgot you couldn't run XMP out the box. I have similar sticks (2x8gb royale 4000 cl 16) and they ran on that board for testing so it's pretty weird.

You could've returned them for something on the QVL/that's guaranteed to work too, but the royale are pretty...just not on the qvl.