EDC = 1, PBO TURBO BOOST bug*
*bug = *feature*.
Some posters over at the X570 Crosshair VIII thread came upon a way to get PBO to boost like never before. LINK
Set PBO into manual mode:
For better tweaked results:
EDC 10 [25-30*]
*EDC 25 is for 3950X, EDC 30 is for 3960X
PPT & TDC aren't important as they can be set whatever you want really but the key aspect here is EDC
We are setting it to 1 Ampere
Some folks have probably noted there have been a bug in regard to EDC in the newer AGESA 188.8.131.52B BIOS. Some have complained that it would not work period. Basically only stock or 0 value which equals the processor fused setting is used. I have found a little flexibility with this setting but not as flexible as it was previously.
In case of a Ryzen 7 3800X
EDC would have a limit of 140A
EDC. There is TDC & PPT as well, PBO uses these limits to set boosting targets and characteristics.
Sadly I myself have noted PBO is gimped and performing beyond subpar to expectations. There are additional Limits on performance other than the available settings exposed in AMD_CBS & AMD_OVERCLOCKING BIOS pages.
What settings we have available ONLY set the targets for non-AVX loads. AVX instructions or software have additional targets and limitations that don't take note of these available settings and behaves in their own way. Probably by design by AMD to protect the more heat and Ampere intensive loads these are. They don't want your to fry your CPU with AVX loads when you use PBO. So these are excluded from your OC settings.
By investigation and testing I've found that Cinebench R20 has a target EDC = 110A & ~70C target to boost. If it hits these targets it's stops boosting and starts to maintain these limits. Simliar target is noted for Y-cruncher 110A EDC, temperature can flex a little but it's similar ~70C. Prime 95 has only a 100A limit for AVX2 & AVX. Some specific loads might exceed these targets. It's unknown how AMD handles the cases when PBO decides to use lower AVX non-user configurable limits. These limits are low!
This is not a OC friendly system! We have here are *locked* PBO restrictions! Not unlocked processors as we all want these to be! (you can only circumvent these restrictions in full manual OC mode, upp till now that is
PBO TURBO BOOST
We can use PBO
and the EDC
setting to create a *feature* super fun TURBO BOOST
We can have EDC setting be so low that the turbo boost algorithm goes FULL THROTTLE
* haywire! *bug
You will get EDC to be allways above it's set target and the boosting algorithm breaks and goes full throttle boost!
What we get is all-core multi-core full boost!
Your CPU will now boost multi-core 4.400-4.550Ghz in most situations for a 3800X sample. (*4.600Ghz attainable)
EDC Limit gets broken and discarded by the algorithm and you get unlocked PBO boosting.
I have seen that EDC will read TDC Amperage limit and you cores will run at their full capabilities! EDC gimp no longer!
What this means is Cinebench R20 will now run up-to 4.4Ghz ALL-CORE rather then the gimped 4.100~4.150Ghz from before because it would hit temperature [~70C ]or EDC [110A] limits for AVX loads.
Multi-thread score will reach 5200-5280points from 5000point scores.
Gaming will see your CPU boost to max clock that your sample is capable off in multithread to what your CPU was before in single thread.*
*sample variances apply, not all chips clock the same, silicon lottery thing
There are caveats, not all CPU's will be stable with this
! GREAT COOLING REQUIRED
Tweaks with voltage and LLC will effect results. Scalar settings has effect on boost. scalar[10x] works best for my 3800X sample.
BEWARE! single thread is throttling.
Single thread or low load will cause the system to throttle as the boosting algorithm is trying to maintain the 1 Ampere limit for EDC. Only works under higher load. Under lower loads the Algorithm is trying to wrestle control to keep EDC to target.
Here is advice: Either
disable C-states to have no lower clock states or
increase EDC target a little to allow the system to have clearance for single-thread loads.
Disabling c-states has best effect for single thread throttling issues but you no longer have c-state C6 used. So higher power draw at idle. Cores will never fully idle at their lowest power state.
I myself found EDC targets between ~
work to make the system go full throttle
under heavy load.
For single thread loads I've found EDC 10
and scalar 10x
has worked best with a 3800X
. It will on occasion throttle to keep the EDC to target at idle or single thread load but all other applications usually work for multi-thread loads to have full boost capabilities.
Others have found that a 3950X
likes EDC 25
and a 3960X
likes one around EDC 30
Picking a too low EDC value will cause more throttling if you have c-state enabled. Using a too high value your CPU will clock down all cores to keep it below your EDC target. More cores usually means you have to pick a higher target for better results.
Another thing is to test CnQ enabled/
disabled, it alters the boost behaviour. Do note some might be stable with one and unstable with the other.
I've myself had better boost clocks with CnQ Enabled
After a tip from gerardfraser
Install and use the Windows Ultimate Power Plan
to have less single-thread throttling with EDC
Beware that idle voltages will not reach the usual 0.200V with this, they will usually stay ~1.000V minimum but you might lessen the single thread throttling we had as issue before.
To add it if you don't have this option run CMD
with administrator privileges
powercfg -duplicatescheme e9a42b02-d5df-448d-aa00-03f14749eb61
Using this power plan isn't necessary but it might give some better results when having c-states enabled.
Others may have had good results with the 1usmus Ryzen Power Plan
with c-states enabled.
TEST AT YOUR OWN RISK!
I take no liability if anything might brake for you. It works satisfactory here for me at the moment.
4.600Ghz single thread & 4.500Ghz+ multi-thread.
Voltages will increase to accommodate the higher clocks.
If you use a 3900X
. You will hit PPT, TDC & CPP/TDP limits which are 140watts & 95A TDC. You will want to increase these from stock limits to not be limited by these as much as matched by your cooling capabilities. Cinebench etc will otherwise throttle @ 140Watts if you don't increase wattage limits and you may only reach 4.1Ghz all-core which isn't the best these can do.
have better behaviour with a EDC 30
have better behaviour with a EDC 20~25
have better behaviour with a EDC 16
have better behaviour with a EDC 10