4). Precision Boost Overdrive
Precision Boost Overdrive is somewhat hard to explain, but we will try to explain it the best we can. It is based upon Precision Boost 2/XFR2, thanks to the changes that were brought from the improved 12nm LP fabrication node. Here is a useful and insightful YouTube video that does a good job explaining what PB2/XFR is, by Robert Hallock (Senior Technical Marketing Manager at AMD).
We will try to explain it ourselves using the following graph:
One of the mayor criticisms of Ryzen first gen is AMD’s Turbo Boost, known as Precision Boost (1000 series). As you can see on the graph, when using more than one core with Precision Boost 1, the frequency on all cores dipped down (therefore less performance). The main change with 2000 series (Pinnacle Ridge) is how turbo frequency works, which is based on some variables.
The CPUs have another option called XFR2 (Extended Frequency 2) a step forward on top of PB2.
Robert Hallock, Senior Technical Marketing Manager at AMD
Using Mr. Hallock words, these “physical limitations” are maximum frequency, temperature and power. Extra performance can be obtained if you play with these limits. Here is an example:
-Let’s say someone uses a stock cooler and under a certain task, the processor works at 3940 MHz on all cores. By changing the stock cooler to e.g. a liquid cooler, the reduction on temperature allows the CPU to work at a higher frequency. E.g. 3980 MHz.
Ryzen Pinnacle Ridge is sensible to temperatures; the lower it is, one can obtain a higher frequency without the need of overclocking the CPU. This is useful due to Pinnacle Ridge’s limited overclock headroom and by manual overclocking, one can lose single-core frequency performance (4.25-4.35 GHz) by using an All-Core 4.2 GHz manual OC.
In high end motherboards, XFR2 is activated by default (I believe this depends on motherboard vendor) while in mobos with a weak VRM, this might be disabled or limited when using a power hungry CPU, such as the Ryzen 7 2700X.
To sum up and I hope you understood, to make it simple, there is three limiters (there is a fourth one but we will keep it simple):
-Maximum Frequency (this varies depending the CPU SKU, Ryzen 7 2700X would be 4350 MHz).
Without modifying anything, the variable a user can play with is temperature (using a better cooling system).
As seen in the diagram, Precision Boost Overdrive amplifies or disables these limiters (such as power, temperature) moving the possible frequency curve even more. Remember that PB2 maximizes the performance on the chip as much as it can depending on the task. With PBO enabled, you might see 4.35 GHz hit more on single core tasks and on productivity workloads and increased frequency on all cores.
I want to highlight one more time, Pinnacle Ridge CPUs are very sensitive to temperatures and you might not see the same results (compared to another user) if he uses a better cooling system.
Within PBO, there is a second variable called Precision Boost Overdrive Scalar (PBO Scalar) and it has a range that starts with 1x up to 10x. I have compared this option before with Goku’s Kaio Ken x10 (King Kai’s Fist x 10). I’m such a nerd. If you choose PBO Scalar 10x, you amplify/disable any limiter the CPU might have.
This brings some secondary effects, such as more generated heat, both in the CPU and the VRM (due to current and higher voltage) and more temperature on the CPU.
The voltage that one can see on a Ryzen 7 2700X en single core such as web browsing, is around 1.44-1.5v. In games, it is around 1.39-1.43v and in heavy productivity workloads is around 1.35-1.38v. Using PBO Scalar 10x reduces the silicon life of the chip (that is no surprise) but it is impossible to measure how much. I have tested PBO for months and is one of the most appealing features Pinnacle Ridge offers.
In the following section, we will show how to configure PBO and how to reduce the impact of higher voltages/temperatures brought by PBO Scalar 10x.
Here is a table and game screenshots with PBO enabled and disabled using this motherboard.
I have a collection of YouTube videos with PBO activated (on those that are specified), some of them combined with BCLK overclocking. Pay attention to the CPU frequencies:
Images with in two games with PBO disabled and enabled.
The Witcher 3 without PBO (Ryzen 7 2700X + GIGABYTE B450 AORUS PRO WIFI)
The Witcher 3 with PBO (Ryzen 7 2700X + GIGABYTE B450 AORUS PRO WIFI)
Player Unknown’s Battleground without PBO (Ryzen 7 2700X + GIGABYTE B450 AORUS PRO WIFI)
Player Unknown’s Battleground with PBO (Ryzen 7 2700X + GIGABYTE B450 AORUS PRO WIFI)