Should i use this?

[Sir Judgementz]

Should i use pbo, tjmax = 85c and curve optimizer -20w? its the 4th choice i have when picking in the bios. New to this, what is expected when doing this and whats the pros vs cons? Iam using a asrock x670e pro RS with a 7800x3d a 4080 gpu and a 1000w psu. thanks for your help

[RONOTHAN##]

22 minutes ago, Sir Judgementz said:

what is expected when doing this and whats the pros vs cons?

It undervolts the CPU and lowers the max temperature it's allowed to reach. Pros are it runs cooler. Cons are it can be unstable and performance might go down slightly in a handful of workloads where the CPU does reach TJMax (these are extremely rare on the 7800X3D though, so not something I'd be too worried about). If you want to give it a shot, sure, but at the first blue screen or weird crash either disable it or go to a more mild curve optimizer setting, though admittedly -20 all core should work on most chip. 

[Sarra]

36 minutes ago, RONOTHAN## said:

It undervolts the CPU and lowers the max temperature it's allowed to reach. Pros are it runs cooler. Cons are it can be unstable and performance might go down slightly in a handful of workloads where the CPU does reach TJMax (these are extremely rare on the 7800X3D though, so not something I'd be too worried about). If you want to give it a shot, sure, but at the first blue screen or weird crash either disable it or go to a more mild curve optimizer setting, though admittedly -20 all core should work on most chip. 

My 5950X will not go past -15 on any core, much less all core.

 

1 hour ago, Sir Judgementz said:

Should i use pbo, tjmax = 85c and curve optimizer -20w? its the 4th choice i have when picking in the bios. New to this, what is expected when doing this and whats the pros vs cons? Iam using a asrock x670e pro RS with a 7800x3d a 4080 gpu and a 1000w psu. thanks for your help

7800X3D isn't going to have PBO available, unless it's an older BIOS. AMD strongly suggests not OCing on any X3D CPU's to prevent cache degradation, as the extended cache is much more temperature sensitive than a typical CPU core.

 

If you can use curve optimizer to get a reduction in voltage to the various cores, and it's completely stable, then you would see longer life, and more stability from the chip, as it would run cooler.

[RONOTHAN##]

Just now, Sarra said:

My 5950X will not go past -15 on any core, much less all core.

 

Yeah, that was my experience on Ryzen 5000, though the Ryzen 7000 series chip tend to have a bit more headroom on them (I've used 6 IIRC, and only one wouldn't do at least -20 all core)

 

1 minute ago, Sarra said:

7800X3D isn't going to have PBO available, unless it's an older BIOS.

??

PBO works just fine on the 7800X3D even on the latest BIOS, you just don't get static voltage or multiplier adjustments. 

[Sarra]

9 minutes ago, RONOTHAN## said:

Yeah, that was my experience on Ryzen 5000, though the Ryzen 7000 series chip tend to have a bit more headroom on them (I've used 6 IIRC, and only one wouldn't do at least -20 all core)

 

??

PBO works just fine on the 7800X3D even on the latest BIOS, you just don't get static voltage or multiplier adjustments. 

Oh. Did they change it, compared to the 5000 series?

[RONOTHAN##]

1 minute ago, Sarra said:

Oh. Did they change it, compared to the 5000 series?

How it works is largely the same, the 7000 series chips just seem to be given a bit more headroom out of the box for whatever reason. The range of supported values is now different (IIRC you can go all the way down to -50 depending on the board rather than maxing out at -30), though that's the biggest between the two. 

 

I've yet to find a chip where -15 doesn't work, so every AM5 system I build ends up with that curve optimizer value (plus performance gains past that point are next to nothing, and therefore I don't care). -20 works on all but the really bad chips in my experience (again, not a ton, but more than most), so if that's a one click option I'd be fine with hitting it, as long as you know to keep an eye out for the random blue screens and crashes that show up at idle when the curve optimizer is unstable. . 

[Sarra]

6 minutes ago, RONOTHAN## said:

How it works is largely the same, the 7000 series chips just seem to be given a bit more headroom out of the box for whatever reason. The range of supported values is now different (IIRC you can go all the way down to -50 depending on the board rather than maxing out at -30), though that's the biggest between the two. 

 

I've yet to find a chip where -15 doesn't work, so every AM5 system I build ends up with that curve optimizer value (plus performance gains past that point are next to nothing, and therefore I don't care). -20 works on all but the really bad chips in my experience (again, not a ton, but more than most), so if that's a one click option I'd be fine with hitting it, as long as you know to keep an eye out for the random blue screens and crashes that show up at idle when the curve optimizer is unstable. . 

I suspect my 5950X isn't a 'silicon winner', as it were, but really, it'll let me do -18 on one core, or it BSOD's.

 

My RX 6800XT is also really... Unhappy with undervolting. It was fine for a long time at 1015mv, then it started crashing constantly, so I had to bump that up. >_>

[Sir Judgementz]

thanks everyone