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PBO limits for 5900X

Forceflow

Forceflow

Forceflow

Associate
Joined
1 Oct 2020
Posts
60
Need some help with my 5900X + Tomahawk X570 combo. Latest bios, cooler is a NH-D15.

I used to just whack PBO on "enabled" in the bios, which resulted in PPT 500, TDC 210, EDC 280. These correspond to "motherboard limits"
This has been how the system has been running happily for about a month or three. I'm reaching 75C in Cinebench R23 continuous loop. Total CPU power stays at about 145W at full load.

Yesterday I was fiddling some more in the BIOS and discovered there was a *second* place where I could enable/disable PBO.
When I put it on "enabled" there, the limits became PPT 500, TDC 210 and EDC 200. Now my system runs hotter, because the CPU power pushes to 160-170W.

I don't understand? Are the motherboard limits safe? Why does my system run hotter when the EDC limit is *lower*? What should I do?
 
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My CR23 scores are low 22k-ish.

Is it dangerous to leave PBO on the default values? PPT 500, TDC 210 and EDC 200.
I'm not much of a tinkerer.
 
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Thank you for all the replies!

Up until yesterday, I had appearantly been running it on PPT 500, TDC 210, EDC 280, which I now see are motherboard values that correspond to "let er' rip".
I never minded these values, I thought these were safe, and they probably are, but they are a wasteful way of (not even getting the best, mind you) better performance in all-core loads. I don't understand why just enabling PBO (what an end-user would do, just set it to "enabled" in BIOS) results in these wasteful values.

What I did *not* understand is how my CPU got hotter and got better all-core boosts when I lowered EDC. More limited, less power draw, right? But after watching and reading a lot I now know that there's a certain optimum to tuning these parameters, and how they work together. After continuous tweaking on just the PBO2 params I landed on PPT 180, TDC 120 and EDC 165. This results in an all-core load of 4,35 Ghz at 72 degrees in CB R23.

Since this is mostly a gaming system, I decided against dialing these in, and just went back to stock. The gains in-game are non-existent or very minimal, even in games that like a lot of threads (warzone, darktide). Lower thermals and lower power usage is beneficial for my chip and for the environment, at the moment.

I'll keep that PBO2 profile handy through for when I encounter a situation in which I need more oompf, and maybe have a look at Curve Optimizer later.

My stock Cinebench R23 all-core scores are in the low 22's, but my RAM probably isn't the best (3600 Mhz with 16-19-19-19 timings) and I've read up that recent AGESA versions introduced some odd clockspeed bugs.

Does this all sound reasonable?
 
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ph123uk said:
Sounds about right to me, although i'd be tempted to set per core undervolts to get your temps better too :)
Click to expand...
I hear you :), but my temps are fine as they are now (hardly hit 70 on CB R23 all core), and curve optimizer, while it looks fun to play with - it also looks like a whole lot of work and a can of possible instabilities to open up.
 
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