Zen 2 Owners Thread!

andy_mk3 · 15 Jul 2019 at 19:42

I gave up on boost. 4.35GHz all 12 cores

i_am_jon · 15 Jul 2019 at 19:54

Sin_Chase said:
More testing and still confused how PBO and XFR are working.
Test 1
AMD CBS > XFR Enhancements PBO set to Enabled
AMD Overclocking > PBO Set to Auto
Any combination of either of those settings together or individually results in the similar sort of outcome. ~4.1Ghz All Core boost and ~4.2ghz single core boost (Still miles away from expected single thread boost clocks though)
Test 2
AMD CBS > XFR Enhancements PBO set to Enabled
AMD Overclocking > PBO Set to PBO Advanced and +200Mhz Core Clock
Multi core is largely unchanged and in the right sort of ballpark with ~4.1Ghz All Core. But single core absolutely nose dives. Am seeing 3.9Ghz single core and significantly degraded Single Core benchmark results. This is the strangest outcome of testing so far.
Test 3
CPU Voltage Auto vs CPU Voltage Normal
Auto voltage results in slightly degraded clocks and benchmark scores for both Multi and Single threaded. Normal seems to have a very slight uplift.
Test 4
CPU Voltage Normal +/- 0mv offset vs CPU Voltage Normal - 0.05mv offset
Setting a - offset reduces core clocks and both Multi and Single threaded benchmarks scores. I envisage pushing an even great - offset will continue to degrade the observed results.
So far the testing is saying leave PBO/XFR Enhancements on Auto/Enabled with a Normal CPU Voltage. I'm still unsure why I am seeing such low Single thread boost clocks.

I'm on similar hardware to you (3900x and x570 Aorus Ultra), bios is pretty much the same at least.

Despite experimenting with the XFR and PBO settings i'm still not seeing boosts over 4.3Ghz (rarely that high to be honest).
So have turned to IF and AMD Overclocking -> manual overclock instead:

Memory: 3,667Ghz 16-17-16-32 T1 @ 1.40v
Infinity Fabric: 1833 (1:1)
CPU: 4,300Ghz set @ 1400 mv
Cinebench R20: 7623 pts

Benchmarks are looking good. Seems stable but needs more testing. Sure there is still room to get the voltages down / speeds up. Temps seem a bit more stable 40-50 idle, 60-75 load.

Don't like the way the FSB is always 99.8Mhz, i'm a bit OCD for nice round numbers!

Edit: Tried going to 4.35Ghz but not stable @ 1.425v, think i'm getting to the limit. Only on air cooling so don't want to put the vCore up too much, already getting to 75 degrees.

Lolik · 15 Jul 2019 at 20:07

andy_mk3 said:
I gave up on boost. 4.35GHz all 12 cores

Cooler init ?

Sin_Chase · 15 Jul 2019 at 20:08

i_am_jon said:
I'm on similar hardware to you (3900x and x570 Aorus Ultra), bios is pretty much the same at least.

Despite experimenting with the XFR and PBO settings i'm still not seeing boosts over 4.3Ghz (really that high to be honest).
So have turned to IF and AMD Overclocking -> manual overclock instead:

Memory: 3,667Ghz 16-17-16-32 T1 @ 1.42v

Infinity Fabric: 1867 (1:1)

CPU: 4,300Ghz set @ 1425 mv

Cinebench: 7623 pts

Benchmarks are looking good. Seems stable but needs more testing. Sure there is still room to get the voltages down / speeds up. Temps seem a bit more stable 40-50 idle, 60-75 load.

Don't like the way the FSB is always 99.8Mhz, i'm a bit OCD for nice round numbers!

Have you seen XMP crazyness? Ive disabled XMP as the reported speeds in the OS were not what XMP was supposed to have set.... Manually used 1.35v 16-16-16-35 1T.

I also note my sub timings are significantly higher in the OS compared to what the BIOS Auto suggestions list.

Do I need to manually set the sub timings also?

i_am_jon · 15 Jul 2019 at 20:16

Sin_Chase said:
Have you seen XMP crazyness? Ive disabled XMP as the reported speeds in the OS were not what XMP was supposed to have set.... Manually used 1.35v 16-16-16-35 1T.

I also note my sub timings are significantly higher in the OS compared to what the BIOS Auto suggestions list.

Do I need to manually set the sub timings also?

I'm on 4x8GB 3600C17 GSkill B-die's. XMP seemed ok about 71ns latency but AIDA showed it as C18. I manually set all the sub-timings from the ryzen calculator (V2 fast).

Might be able to get Infinity Fabric a little higher with more volts to it but that's where the bios settings started getting more complicated.

See thread here!

cliffy · 15 Jul 2019 at 20:39

I also tried undervolting my CPU. dropped it down to 1.1V and saw bost sppeds on 2 cores greater the 4.4Ghz. Benchmarks were signifigantly lower though. I think its just because boosts are higher due to the lower temps and lower vcore but cannot be sustained. I also get much better stability with the SOC at 1.1v

Eatchipz · 15 Jul 2019 at 20:44

This guy is getting stunning results from his 3900x when undervolting it 1.0v!

1.3v seems to be the lowest my 3700X can go to without affecting benchmarks.

Sin_Chase · 15 Jul 2019 at 21:41

The above is not all it seems to be and glosses over actual performance impact.

Have a read of the following which confirms my findings also. Higher boost clock, less heat, significantly less performance.

https://www.reddit.com/r/Amd/commen...with/?utm_medium=android_app&utm_source=share

DragonQ · 15 Jul 2019 at 21:56

Yeah it really does seem that you can't tweak the CPU performance much. Either stock, PBO for a tad more performance for significantly higher heat/power, or all core overclock sacrificing some low-threaded performance.

Captain · 15 Jul 2019 at 21:58

Should be due some compensation then if AMD can't provide the quoted boost clocks

a nice 50% refund would do me nicely.

Grim5 · 15 Jul 2019 at 22:00

Eatchipz said:
This guy is getting stunning results from his 3900x when undervolting it 1.0v!

1.3v seems to be the lowest my 3700X can go to without affecting benchmarks.

He didn't show any performance - which naturally would have suffered massively from the undervolt

willhub · 15 Jul 2019 at 22:08

Could it be a case of 4GHz and play how low can you go on the voltage is going to be the sweet spot for performance and temp?

Sin_Chase · 15 Jul 2019 at 22:09

Clov!s said:
Should be due some compensation then if AMD can't provide the quoted boost clocks a nice 50% refund would do me nicely.

My 3900x not even reaching the box boost speeds of 4.4 in any scenario takes the shine off a little...

Captain · 15 Jul 2019 at 22:12

Sin_Chase said:
My 3900x not even reaching the box boost speeds of 4.4 in any scenario takes the shine off a little...

The 3900x is supposed to boost to 4.6 isn't it? Sure it says 4.6 on my box.

Sin_Chase · 15 Jul 2019 at 22:13

Clov!s said:
The 3900x is supposed to boost to 4.6 isn't it? Sure it says 4.6 on my box.

Not even seeing 4.4! Highest I've seen is 4.2.

opethdisciple · 15 Jul 2019 at 22:16

It's a bit naughty that AMD exaggerate the boost speeds. My 2700x has an advertised boost of 4.3GHz. I've not seen much over 4.1GHz.

Journey · 15 Jul 2019 at 22:16

Clov!s said:
The 3900x is supposed to boost to 4.6 isn't it? Sure it says 4.6 on my box.

Yep, but doesn't seem to happen 99.99% of the time. It is like something that will be resolved with newer BIOS releases.

arc@css · 15 Jul 2019 at 22:17

Clov!s said:
The 3900x is supposed to boost to 4.6 isn't it? Sure it says 4.6 on my box.

I don't think I've seen anyone on here reporting the advertised clock of 4.6 (very, very few anyway). :/

motiv · 15 Jul 2019 at 22:18

Sin_Chase said:
Not even seeing 4.4! Highest I've seen is 4.2.

Crikey, that's a bit pants. PBO is terrible for reaching boost speeds but something seems wrong with that. My lowly 3700 gets boosted for a microsconf to 4.3 in all of the cores at some point when the others are asleep.

opethdisciple · 15 Jul 2019 at 22:18

I guarantee it wont be 'resolved' by bios updates. It's probably a theoretical max based on ultra optimal conditions (and probably a golden chip). Of which the majority of us we'll never have.