Overclocking - Why not to OC AMD/Ryzen 3000 Series Systems | PCSPECIALIST

Overclocking - Why not to OC AMD/Ryzen 3000 Series Systems

Scott

Spamtastic
I thought I would put forward a simple explanation of why not to OC a 3000 series AMD system. Unlike Intel, AMD list their boost clocks on the expected "BEST" core, rather than the worst core.

How Intel boost clocks are determined:

When Intel mark on their boost frequency on the box, it's based on the expected minimum boost clock of any of the cores. That is to say, when boosting on an 8 core chip.... any of the 8 cores will be able to hit the boost frequency within the standard running parameters. It is VERY rare to have an Intel chip not manage at least the maximum boost frequency across the cores. When overclocking an Intel chip, you can be confident that every one of the cores is able to at least run at the defined boost frequency.... it would just require more power to run them all at the same time.


How AMD boost clocks are determined (and the difference):

The boost clocks for AMD are pretty much the opposite and AMD uses very clever AI boost technology to move the processes around the cores for the optimum use. In an 8 core chip, the boost frequency is listed as the expected BEST of the cores available. When a process requires a bit of boost frequency, the AI shifts the process onto the BEST core, which then boosts to the highest frequency it can. In a chip with a boost frequency of 4.3, only 1 of the cores is expected to manage this frequency, and due to the "up to" statement, it isn't guaranteed. When manually overclocking the norm is to have the same frequency across all of the cores. Unfortunately, this means that you are limited by the LEAST performing core. In an up-to 4.3Ghz chip that could be 4.1ghz, thus losing you 0.2ghz where the AI would select the core that can handle this.

As a working example of Intel:

Core 1 - 5.2Ghz
Core 2 - 5.4Ghz
Core 3 - 5.1Ghz
Core 4 - 5.1Ghz
Core 5 - 5.1Ghz
Core 6 - 5.5Ghz
Core 7 - 5.3Ghz
Core 8 - 5.1Ghz

The above chip would be above the requirements of the advertised 5.0Ghz boost using Intels description as every core can at least meet the boost frequency. If you were to overclock this chip you would easily manage 5.1Ghz across all of the cores using standard voltage settings. This is a reasonably well binned chip and 5.3Ghz would likely be possible on good cooling with voltage adjustments.


As a working example of AMD:

Core 1 - 4.1Ghz
Core 2 - 4.2Ghz
Core 3 - 4.1Ghz
Core 4 - 4.3Ghz
Core 5 - 4.1Ghz
Core 6 - 4.2Ghz
Core 7 - 4.0Ghz
Core 8 - 4.0Ghz

The above chip would meet the requirements of the advertised 4.3Ghz boost using AMDs description as the best performing core can at least meet the boost frequency. It's important to note at this stage that not all AMD chips can actually hit their target boost frequency as it's all based on statistical analysis of the chips. The Up To with AMD is not a given. The higher end chips often end up 0.1 or 0.2Ghz below their advertised maximum boost frequency (Although I believe there have been BIOS updates released to try and remedy this). When a heavy process is recognised by the AI, it automatically shifts the process to core 4 to give it the highest output of 4.3Ghz. The AI does a great job of managing the processes across the cores for the most efficient output. If you were to overclock this chip with stock voltages you would only manage a 4.0Ghz all core clock. If you increased the voltages you would be unlikely to get to the 4.3Ghz boost across all cores without putting silly voltage into the silicone. At this point you need incredible cooling, hence why anyone overclocking these chips always has the best coolers money can buy. Even using LN2 it's tricky to get extreme frequency that is often made with Intel on standard coolers.

Hopefully that makes some sense and allows better reasoning for why I, and many others, would never recommend overclocking an AMD system.
 
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