Ryzen 3950x can only hit infinity clock of 1600?

[Mannymac]

Hi guys,

I'm slowly giving up on my new system.

I've got a AS Rock x570 Creator motherboard running a Ryzen 3950x wiith 2x16 gb 3600 Mhz Corsair Vengeance LPX C18 memory sticks.
With XMP enabled I can't get the CPU and memory to run in coupled mode, thus incuring laatency penalties.

As you can see in the screenshot from Ryzen Master I can only run 1600 fabric clock at 1800 memory clock. I tried to increase the fabric clock in the bios to 1800 so it couples and then my PC won' boot!
With this setup I get into the area where Ryzen halves the Infinity clock which you can see in the unicore screenshot from CPU-Z

I have also attached a full CPU-Z report of my machine.

Anbyody got any idea what the issue is? Is the CPU bad? I've done the diagnostics with ClockTuner for Ryzen that gave my CPU a silver rating so it should be able to run that fabric clock?

All help much appreciatedd.

 

[bug]

Well yes, 1600 is usually the limit for Zen2. Anything above that needs a dose of luck. The sweetspot is 1800, but I don't think all CPUs can do that.

 

[Mannymac]

Would I then be better off just getting a 3200 Mhz C14 stick like this one:

G.SKILL TridentZ Series F4-3200C14D-32GTZ 32 GB (16 GB x 2) DDR4 3200 MHz CL14 1.35V Memory Kit - Multi Colour - G.SKILL

Buy G.SKILL TridentZ Series F4-3200C14D-32GTZ 32 GB (16 GB x 2) DDR4 3200 MHz CL14 1.35V Memory Kit - Multi Colour at Amazon.

www.amazon.co.uk

Lower latency, but less memory speed but at least I know I can couple it?

 

[TheLostSwede]

Well yes, 1600 is usually the limit for Zen2. Anything above that needs a dose of luck. The sweetspot is 1800, but I don't think all CPUs can do that.

Huh? That's not true, you're calculating things wrong now.
1600/3200 is guaranteed to work.
1800/3600 is the "sweetspot" in terms of cost/performance
1900/3800 is possible for many, but not all.

 

[bug]

Don't worry too much about it, the performance difference isn't worth the hassle.
But yeah, Corsair is a notoriously bad match for Zen. Not sure why, they're usually a good brand.
Also make sure your UEFI is updated to the latest version, those improve memory compatibility from time to time.

 

[TheoneandonlyMrK]

Would I then be better off just getting a 3200 Mhz C14 stick like this one:

G.SKILL TridentZ Series F4-3200C14D-32GTZ 32 GB (16 GB x 2) DDR4 3200 MHz CL14 1.35V Memory Kit - Multi Colour - G.SKILL

Buy G.SKILL TridentZ Series F4-3200C14D-32GTZ 32 GB (16 GB x 2) DDR4 3200 MHz CL14 1.35V Memory Kit - Multi Colour at Amazon.

www.amazon.co.uk

So much lower latency but less speed but at least I know I can couple it?

Corsair Lpx have a mixed history , a fair few users have ended up here with issues, plus it sounds like you have only tried Xmp mode, have you tried manually inputting the first four primary timings leaving others on auto, and upping ram voltage to 1.35V.
Oh and setting the memory speed to its Xmp rated speed obv.

So mostly Xmp speeds but done manually with almost all timings on auto , for clarity.

 

[TheLostSwede]

Would I then be better off just getting a 3200 Mhz C14 stick like this one:

G.SKILL TridentZ Series F4-3200C14D-32GTZ 32 GB (16 GB x 2) DDR4 3200 MHz CL14 1.35V Memory Kit - Multi Colour - G.SKILL

Buy G.SKILL TridentZ Series F4-3200C14D-32GTZ 32 GB (16 GB x 2) DDR4 3200 MHz CL14 1.35V Memory Kit - Multi Colour at Amazon.

www.amazon.co.uk

Lower latency, but less memory speed but at least I know I can couple it?

Did you update the UEFI to the latest version? A lot of early UEFI releases were limited in terms of what IF speeds you could run at.
Did you actually set the IF clock in the UEFI? Or is it just on auto? In theory all boards should do 1800MHz on auto, but anything above that is a manual setting. However, this varies between the board makers.

What's the model name of that RAM? Does it have a Z in it? If not, it's not guaranteed to work properly with Ryzen.

 

[Mannymac]

Thanks for all the quick answers.
This is my RAM

Corsair Vengeance LPX Black 32GB 3600MHz AMD Ryzen Tuned DDR4 Memory Kit

Buy from Scan - 32GB (2x16GB) Corsair DDR4 Vengeance LPX Black, PC4-28800 (3600), Non-ECC Unbuffered, CAS 18, 1.35V, AMD Ryzen Optimised

www.scan.co.uk

Yes uefi is the latest 3.13 for the as rock creator x570. I also tried the beta 3.15 which didnt change things. I got a 3733 cas 14 coming tomorrow from g skillz just to see if the corsair is the bottleneck.

Yes i did try the timings and mclock to set manually in the bios. While we are at it: Taiphoon booster gives me a Hynix 8gb / 1 die density .read out.

What is that in dram calculator? I went with Hynix DJR to be safe.

 

[Toothless]

Honestly, run 1600/1600 and tighten timings to CAS14 or 15 if you can, and run it like that.

 

[FinneousPJ]

AMD spec is up to 1600 MHz. Anything more is extra.

 

[Mannymac]

Ahhh here we go. This is my Corsair model number:
CMK32GX4M2D3600C18

No Z in sight. And according to the info by the Lost Swede (seriously, you are awesome) here: https://www.techpowerup.com/forums/threads/psa-corsair-lpx-and-amd.274300/

That makes me one of the unlucky ones. Anybody got recommendations for a good 3600Mhz c16 ram?

Would this one work?

32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB)

Buy 32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB) online from MemoryC at low prices. Worldwide shipping, money back guarantee, in-stock guarantee!

www.memoryc.com

 

[TheLostSwede]

Ahhh here we go. This is my Corsair model number:
CMK32GX4M2D3600C18

No Z in sight. And according to the info by the Lost Swede (seriously, you are awesome) here: https://www.techpowerup.com/forums/threads/psa-corsair-lpx-and-amd.274300/

That makes me one of the unlucky ones. Anybody got recommendations for a good 3600Mhz c16 ram?

Would this one work?

32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB)

Buy 32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB) online from MemoryC at low prices. Worldwide shipping, money back guarantee, in-stock guarantee!

www.memoryc.com

Well, Corsair seemingly claim that those are for Ryzen and Intel, but its' clearly not one of the good kits.

VENGEANCE® LPX 32GB (2 x 16GB) DDR4 DRAM 3600MHz C18 Memory Kit - Black

VENGEANCE LPX memory is designed for high-performance overclocking. The heatspreader is made of pure aluminum for faster heat dissipation, and the eight-layer PCB helps manage heat and provides superior overclocking headroom.

www.corsair.com

As your RAM is clocking at 3600MHz, I doubt the issue is the RAM though and there's no reason why your IF shouldn't working at 1800MHz, outside of the motherboard/UEFI. Even the really low bins of Ryzen 3 CPUs can do 1800MHz IF.

 

[Mannymac]

Hmm that is depressing to hear.

Have you got any idea what I can look for in the motherboard to tweak so I can reach 1800mhz?

Just did a membench and AIDA test and here are the results.

Based on what I got here does anbybody think my uneven ratios have a big impact on real life performance?

 

[thesmokingman]

It's your ram. The IMC on your chip, hell the whole chip is highly binned. It should should do 1900 w/o batting an eyelash. For ex. my just retired 3900XT did 1900 fabric on stock voltage. The 3900XT is similar same as to the 3950X.

Looking at your aida, if I were you I'd stopped trying to hit 1800 and focus on tightening those high latencies. You're at 86ns, stock is 70ns-72ns, so you're actually worse off with that ram. Work on lowering that ram latency at 3600 or simply get good ram.

 

[Mannymac]

Thanks for looking at the benchmarks @thesmokingman !

Sorry I'm new here. Highly binnded Imc on a cpu indicates good ram?

Got these guys arriving at mine tomorrow:

32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL14 1.45V Quad Channel Kit (4x8GB)

Buy 32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL14 1.45V Quad Channel Kit (4x8GB) online from MemoryC at low prices. Worldwide shipping, money back guarantee, in-stock guarantee!

www.memoryc.com

Will report back if that solves it.

 

[thesmokingman]

Thanks for looking at the benchmarks @thesmokingman !

Sorry I'm new hear. Highly binnded Imc on a cpu indicates good ram?

Got these guys arriving at mine tomorrow:

32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL14 1.45V Quad Channel Kit (4x8GB)

Buy 32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL14 1.45V Quad Channel Kit (4x8GB) online from MemoryC at low prices. Worldwide shipping, money back guarantee, in-stock guarantee!

www.memoryc.com

Will report back if that solves it.

IMC = internal memory controller, ie. generally speaking the imc includes the inifinity fabric. Thus a higher quality level imc means a higher fabric speed.


Why are you buying those? Are you staying at 3600mhz? Holy carp that ram is expensive. You should buy ram rated for the speed you want to run btw...

 

[Mannymac]

Buying those to see if it works and what the improvement really is. Then seeing if I can overclock. The idea is to buy the highest quality I can get to see the real life improvement. I do a lot of pro audio work at high sample rates where super fast ram speeds are important.

If that works I will try these here, compare and then probably send the expensive ones back:

32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB)

Buy 32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB) online from MemoryC at low prices. Worldwide shipping, money back guarantee, in-stock guarantee!

www.memoryc.com

Just really interested to see if cl14 Vs cl16 makes a difference when running real time audio at high loads. Super niche use case, I know.

 

[Fluffmeister]

I bought these from Overclockers, and they have worked great for me 3600Mhz CL16 timings and guaranteed Samsung B-dies, selected the profle in the BIOS and all is well, they sell some with tighter timings but I just wanted to hit the sweetspot as I just intend to let my 3700X do it's thang.

Team Group 8Pack Edition 16GB (2x8GB) DDR4 PC4-28800C16 3600MHz Dual Channel Kit - Black/

TDPGD416G3600HC16ADC01, 3600MHz RAM Speed, CAS 16-16-16-36 Timings, 1.20-1.40v VDIMM, Samsung B-Die, Ideal for 3rd gen Ryzen, Ryzen 3000 8 Pack Approved, Lifetime Warranty with OcUK.

www.overclockers.co.uk

 

[thesmokingman]

Buying those to see if it works and what the improvement really is. Then seeing if I can overclock. The idea is to buy the highest quality I can get to see the real life improvement. Indo a lot of pro audio work at high sample rates where super fast ram speeds are important.

If that works I will try these here, compare and then probably send the expensive ones back:

32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB)

Buy 32GB G.Skill DDR4 Trident Z Royal Gold 3600Mhz PC4-28800 CL16 1.35V Dual Channel Kit (2x16GB) online from MemoryC at low prices. Worldwide shipping, money back guarantee, in-stock guarantee!

www.memoryc.com

It's not going to make a difference, the ram speed... we're talking minute differences. The latency is more important. I think ppl get caught up in this ram thing on AMD. And if you're doing pro work, you don't want to be oc'ing for the sake of oc'ing anyways. Fast yet reliable is what I'd expect.

That said, why are you buying from that company? Do you like the Royals particularly or something? Highest quality is not the correct term for this, it's binning. And for binned ram, you buy it for the ram speed you intend to run. And that ram 3600 cas 16 ram you picked from that shop is ludicrously overpriced, that shop is overpriced man.

 

[Mannymac]

Don't want to oc. Thanks for the over lockers link , just ordered those to compare !

Both are 3600 MHz , one c14 one c16. Let's just see if there is a difference . If it's not I can send them back no problem.

I bought these from Overclockers, and they have worked great for me 3600Mhz CL16 timings and guaranteed Samsung B-dies, selected the profle in the BIOS and all is well, they sell some with tighter timings but I just wanted to hit the sweetspot as I just intend to let my 3700X do it's thang.

Team Group 8Pack Edition 16GB (2x8GB) DDR4 PC4-28800C16 3600MHz Dual Channel Kit - Black/

TDPGD416G3600HC16ADC01, 3600MHz RAM Speed, CAS 16-16-16-36 Timings, 1.20-1.40v VDIMM, Samsung B-Die, Ideal for 3rd gen Ryzen, Ryzen 3000 8 Pack Approved, Lifetime Warranty with OcUK.

www.overclockers.co.uk

Thanks for that link!

My situation right now is that I can't even hit 1800 on the infinity fabric. So I'm just sticking the lowest latency 3600mhz Samsung b die to in to see if that solves it. Will probably send the over 400 pounds ones back and get 3600mhz c16 but for now I just want to see if going to the extreme end of the ram spectrum solves my asynchronous speed problem

 

[TheLostSwede]

Hmm that is depressing to hear.

Have you got any idea what I can look for in the motherboard to tweak so I can reach 1800mhz?

Just did a membench and AIDA test and here are the results.

Based on what I got here does anbybody think my uneven ratios have a big impact on real life performance?

Lots of arguments here, yet no-one spotted this.

Your IF is running at half speed (1:2), hence the terrible latency.
You might want to check your UEFI, as some setting is wrong, as at these kind of memory speeds, you should be running 1:1 no problem.

Yes, you don't have great RAM, but I'm certain you should be able to tighten the timings a bit.

 

[Caring1]

Lots of arguments here, yet no-one spotted this.

View attachment 177180

Your IF is running at half speed (1:2), hence the terrible latency.
You might want to check your UEFI, as some setting is wrong, as at these kind of memory speeds, you should be running 1:1 no problem.

Yes, you don't have great RAM, but I'm certain you should be able to tighten the timings a bit.

OP mentioned it in the first post.
Uncore frequency half the IF.

 

[TheLostSwede]

OP mentioned it in the first post.
Uncore frequency half the IF.

Sure, but this is clearly a settings problem, it can't be the RAM that forces the IF into 1:2 mode at these speeds.

 

[Mannymac]

It seems it does @TheLostSwede , when I set my RAM to 3200 Mhz to test my IF clock they synch up and both run at 1600. Got better RAM coming tonight and will report back. Thanks guys, really apprciate all the knowledge and help here!

 

[dont whant to set it"']

It's more of a motherboard issue than anything else, except for some corsair ram.
I've sort of been in a similar situation having a 4400mhz ram kit available, above 3200mhz to MHz 3333, POSTed but even so it was very unstable.(B550)
Miraculously I got the kit up to 3600mhz with odd ratios like 1:1/2:1 on an x370, but that wasn't the main mb back then , so I returned that kit.