Question What is the reason for PBO when undervolting if the temperature is just going to go up again?

[mrfent]

Hi everyone!

I recently built a new PC and I’m trying to undervolt it for better longevity. I’ve run multiple stress tests, benchmarks, and stability checks across different configurations, but I’m still not entirely sure what the point of Precision Boost Overdrive is.

Here’s what I tested:

• Default settings: Cinebench 2024 score of 1339 with an average temp of 85°C.
• With PBO enabled at +200MHz, limited to the motherboard, curve optimizer set to -20, and thermal limit set to 80°C, the system was stable and scored 1375, with an average temp of 80°C.
• Then I reset all BIOS settings related to PBO and only enabled curve optimizer -20, and I got a score of 1351—but with average temps down to 68°C.

This has left me confused. Was the first configuration considered overclocking? Is it better to just stick with the curve-only setup? It seems cooler, yet still got a better performance score than default settings.

My goal is to reduce CPU temperatures while maintaining equal or slightly better performance. Any advice on whether I should continue tweaking PBO (and what/how) or leave it as is?

System Specs:

• CPU: AMD Ryzen 7 9800X3D
• Cooler: Thermalright Phantom Spirit EVO
• Motherboard: MSI MAG B850M Mortar WiFi
• RAM: Corsair Vengeance 32GB DDR5 6000MHz CL30
• Storage: Kingston FURY Renegade 2TB
• GPU: PNY RTX 4070 Ti Super
• PSU: Corsair RM850x 3.1 (2024)
• Case: Lian Li A3
• OS: Windows 11
• Monitor: Xiaomi G Pro 27i

Thanks in advance for any guidance! 😊

 

[TerryLaze]

This has left me confused. Was the first configuration considered overclocking?

Yup,
PBO =overclocking by lifting the power limits and letting all cores boost higher than they would with the power limits but not above their maximum allowed clocks.
PB = normal turbo boosting

https://gamersnexus.net/guides/3491-explaining-precision-boost-overdrive-benchmarks-auto-oc

 

[mrfent]

Yup,
PBO =overclocking by lifting the power limits and letting all cores boost higher than they would with the power limits but not above their maximum allowed clocks.
PB = normal turbo boosting

https://gamersnexus.net/guides/3491-explaining-precision-boost-overdrive-benchmarks-auto-oc

I see, well I'm not looking to overclock, I'm very happy with the out of the box performance of the CPU. What I do care about is temperature and so that's why I'm here asking for help

 

[punkncat]

I feel your pain on this, although an older CPU.

I picked up one of the 5900XT on that basically giveaway deal they ran on Amazon. I had to run a -.1 offset to voltage and turn off PBO in two different places in order to get temps in line and keep the chip from throttling which basically defeats the whole point. Having done so I see all cores still hit 4.8+ and very seldom one or two cores will be close to 5. The plus side of that being that even on a Dark Rock Pro 4 air cooler I don't see the CPU heat over the mid 70's for any load be it real gaming or workload or synthetic benchmarks.