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Two different PBOs with vastly different behavior - what the heck?

nantes
Level 8
In my BIOS for the B550-E Gaming you can reach "Precision Boost Overdrive" via two different routes: the "AI Tweaker" tab or or the "Advanced" tab. Both have nearly the same options except that the latter allows you to change the Curve Optimizer function while the former does not (which is silly, and a complaint I've made here).

Upon further testing I have noticed that both PBOs behave vastly differently: turning the one under AI Tweaker on, my 5600x's power consumption shoots from 76W (stock draw) to 95W or more (it's also worth noting that turning on "AMD Performance Enhancer" under the same AI Tweaker menu has the same effect, and I've found no practical difference between enabling either that or PBO). Whereas turning on the PBO under the Advanced tab on with the same sub-options (and Curve Optimizer on Auto), power draw stays at 76W, the normal power draw constraint. It is clear that despite being named the same and having very similar sub-options, these two features are completely different. Further evidence of this is that they don't sync; if you disable PBO in one, it will not disable on the other.

Can someone knowledgeable please explain this mess?

Example images just to show the two different paths (the values for the options are not what I'm using):

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9 REPLIES 9

Kelutrel
Level 11
In my experience, the two menus overlap but the behavior is identical when set to the same values, also the help text on the "Precision Boos Override" and "PBO Limits" fields may help explain you the difference in watts that you observed.

My suggestion would be to keep the settings in "AI Tweaker\Precision Boost Overdrive" all on auto, and just use the ones in the AMD submenu, I have a different motherboard though.

I just played around with these settings today with my Ryzen 5900X and X570-E Gaming motherboard. Seems the two different sections serve two different purposes. The one under AI Tweaker is a milder version that has less performance gains and would not void the warranty compared to the one under the Advanced menu Overclock section which clearly gives a warning that changing the settings in this section will void the warranty. I ended up disabling the PBO options in the AI Tweaker section and manually set the PBO options in the Advanced Overclocking section. What actually even makes a bigger difference in the results is using the Curve Optimizer along with PBO to get optimized frequencies and voltages/temperatures. I ended up using a +150 MHz boost with a Curve Optimization of negative 18 for each individual core. With this I got results of 4700 MHz single core and 4350 MHz all-core clockings stable with no increase in temperatures compared to stock settings under full load or otherwise. I have a Thermaltake 240mm AIO Cooler which does a pretty good job keeping temps stable.

I watched this YouTube video below that does a great job explaining what PBO and Curve Optimizer do, and how to find the optimal settings for your system.

https://www.youtube.com/watch?v=dU5qLJqTSAc&t=995s

I tried the same settings in both menu and the result is quite different.

My guess is:

1. in the Advanced menu, probably it comes from AMD directly and it includes curve optimizer.
2. in the Extreme AI Tweaker, I guess it is the Asus own version.

I end up using the PBO and curve optimizer in the Adanced menu and I leave all the settings in "auto" in the extreme tweaker. It gives me the best overall stable performance.

I tried to use the ai suite 3 to overclock the mobo but the result is not as good as that from Advanced menu.

Banditt1976 wrote:
with a Curve Optimization of negative 18 for each individual core. With this I got results of 4700 MHz single core and 4350 MHz all-core clockings stable
https://www.youtube.com/watch?v=dU5qLJqTSAc&t=995s


That sounds like witchcraft to me; even a curve optimizer of -10 all cores, while stable on stress tests and general use, will occasionally turn off the computer during gaming for me. Will have to watch the video you linked and learn more.

Btw why did you do -18 on each core individually instead of all cores? Isn't it the same in practice?

nantes wrote:
That sounds like witchcraft to me; even a curve optimizer of -10 all cores, while stable on stress tests and general use, will occasionally turn off the computer during gaming for me. Will have to watch the video you linked and learn more.

Btw why did you do -18 on each core individually instead of all cores? Isn't it the same in practice?


What games are you playing that are crashing? I did it at each core to start with because supposedly you can have the faster core(s) at a different setting and get better results. I tried doing that and my system would never boot so I gave up on doing that. I guess I could set it to all cores and see if it is the same performance.

I have a 5800X and the settings in curve optimizer is: -22 (best core), -25 (second best), -28 (all other cores)

It gives me 4950MHz single core and 4650MHz all core stable performance.

I did not tweak PBO, just Advanced-motherboard.

I am a bit lazy to go deep to tweak individual parameters to get another 50 or 100 MHz.

I am quite happy with the current performance.

isaactwn wrote:
I have a 5800X and the settings in curve optimizer is: -22 (best core), -25 (second best), -28 (all other cores)
It gives me 4950MHz single core and 4650MHz all core stable performance.



When I tried to go to negative 20 or more my system wouldn't POST with my RAM running at 4000 MHz. What are your other system specs for comparison?

What BIOS settings/timings are you using for your RAM to get 4000 MHz stable?

- Dark Hero mobo
- AMD 5800X cpu
- G.skill F43600C16-D32GTZN X 2 (16GB X 2) overclocked to 4000MHz, Fclk locked to 2000MHz
- Asus 360LC AIO
- Corsair 850M PSU
- Asus 1660 Super Phoenix GPU (could not buy RTX 3080)

Kelutrel
Level 11
Note that the curve optimizer settings depends heavily by the luck and the cpu bin of the owner.

A zen3 cpu can be stable with the PBO values all set to negative 30, while another zen3 cpu of the same model may not allow to go under negative 5 before encountering random reboots.

It's like the old overcloking bins, where a cpu could be stably overclocked to 30% more mhz, while another cpu of the same model would only reach 10% overclock before being unstable.