Silicon Lottery: Only 6% of AMD Ryzen 9 3900X CPUs Capable of 4.2 GHz

[Tsing]

Manual overclockers are welcome to try their hand at squeezing extra performance out of AMD's Ryzen 9 3900X, which has a base clock of 3.8 GHz, but they shouldn't expect to hit frequencies beyond 4 to 4.1 GHz at safer voltages. Binned-CPU retailer Silicon Lottery found that only 35% of their chips managed to hit 4.15 GHz (1.237 V), while a paltry 6% reached 4.2 GHz (1.250 V).

4 GHz seems to be guaranteed, however, as Silicon Lottery saw a 100% pass rate for that frequency at 1.2 V. 4.05 GHz is also doable (87% @ 1.212 V), but the odds begin turning poor at 4.10 GHz (4.10 GHz @ 1.225 V) and upward.

All Ryzen 9 3900X CPUs tested by Silicon Lottery were able to hit 4GHz across all-cores (via Techquila). 87% could hit 4.05GHz, which is a sharp drop-off for a marginal clock speed increase. However, the most drastic pass rate decline is between 4.10GHz and 4.15GHz.

 

[Dan_D]

If true, that makes me think that the review sample chips were cherry picked. I think most reviewers hit 4.3GHz on all cores. I know I did.

 

[GSDragoon]

If true, that makes me think that the review sample chips were cherry picked. I think most reviewers hit 4.3GHz on all cores. I know I did.

Yeah, I've been thinking this for a while now. Data from the general public seems different than reviews. Not that the reviewers are doing anything wrong or even know.

 

[Dan_D]

Well, we never know until we see what the general public reports on the forums. All we have to go on are the chips we are sent. Sometimes we buy retail chips for testing, but that depends on budget and what our specific needs are. All of our Intel CPU's are currently retail, but none of our AMD CPU's are. My Ryzen 2700X is literally the only retail AMD chip I have.

 

[keljian]

Are you sure this is not a voltage thing? I have heard reports of 3900x chips hitting higher voltages when boosting

 

[Dan_D]

Are you sure this is not a voltage thing? I have heard reports of 3900x chips hitting higher voltages when boosting

Yes they do, which AMD says is normal.

 

[Zarathustra]

I want to know how high of a percentage of their chips actually are able to hit advertised boost clocks.

 

[Dan_D]

I want to know how high of a percentage of their chips actually are able to hit advertised boost clocks.

The motherboard seems to be the cause of this in some cases, although at least one vendor (ASUS) I talked to has no idea why the correct boost clocks don't occur on some boards with some specific processors.

 

[Bloax]

When doing all-core on Zen2, don't go above 1.325v (with LLC) unless you want your chip to degrade very quickly.

My 3600 went from barely squishing out 4.15 Ghz @ 1.375v with fCLK topping out at 1866 to not even being able to sustain 4.125 Ghz at that voltage and throwing out memory errors at 1866 fCLK all in less than a month ; )

Ah - and yes; unless you're on a 3600, you may find per-CCX overclocking to be much more fruitful than being limited to your most citrus-flavoured CCX for an "all core" overclock.
Plenty of 3900x processors seem to have a CCX or two which can do 4.4+ Ghz at 1.3v, now you just need a program like Process Lasso to auto-assign processor affinities to certain processes you wish to make use of them.

 

[Strelok]

If true, that makes me think that the review sample chips were cherry picked. I think most reviewers hit 4.3GHz on all cores. I know I did.

Wouldn't surprise me. People always talk **** about Intel's shady tactics, but seem to just gloss over AMD's ****. Maybe this is just a conspiracy theory, but I'm pretty sure they have planted a lot of bots on reddit and other sites to upvote/downvote and try to justify things like bad launch drivers/BIOSes. If I remember correctly they also gave certain favorable reviewers earlier samples or earlier embargos than others with Threadripper.

But, Silicon Lottery could have different criteria for stability than reviewers. Either way, these CPU's aren't great for OC'ing.

 

[Dan_D]

Wouldn't surprise me. People always talk **** about Intel's shady tactics, but seem to just gloss over AMD's ****. Maybe this is just a conspiracy theory, but I'm pretty sure they have planted a lot of bots on reddit and other sites to upvote/downvote and try to justify things like bad launch drivers/BIOSes. If I remember correctly they also gave certain favorable reviewers earlier samples or earlier embargos than others with Threadripper.

But, Silicon Lottery could have different criteria for stability than reviewers. Either way, these CPU's aren't great for OC'ing.

Some sites like Gamer's Nexus had CPU's well in advance of others.

 

[Strelok]

Some sites like Gamer's Nexus had CPU's well in advance of others.

All of them? They use other sources to get CPU's that AMD doesn't supply IIRC.

 

[Dan_D]

All of them? They use other sources to get CPU's that AMD doesn't supply IIRC.

I have no idea.