![]() ![]() In case there is clear evidence of biasing taking place on certain motherboards or their bios versions, please contact the manufacturer and ask them to remove the telemetry biasing from the bios. A suggested workload to get a stable and reproducable deviation metric is Cinebench R20 NT, with the HWiNFO sample rate set to less or equal to 1000ms.Īs of now, outside of certain MSI motherboards, the biasing isn't end-user controllable. ![]() That is due to the typical measurement accuracy of the VRM controller telemetry, and also due to the highly advanced and fast power management on Ryzen CPUs, that not only result in extremely low idle, but also in extremely rapidly changing power consumption. Obviously, the figure can be greater than 100%, but for the obvious reasons it rarely isĪs stated before, this metric is only valid during a relatively stable near-full-load condition. So, if you see an average value that is significantly lower than ~ 95% there is most likely intentional biasing going on. A ballpark for a threshold, where the readings become suspicious is around ±5%. When the motherboard manufacturer has both properly calibrated and declared the reference value, the reported figure should be pretty close to 100% under a stable, near-full-load scenario. The displayed figure is a percentage, with 100.0% being the completely unbiased baseline. HWiNFO will display "Power Reporting Deviation" metric under the CPUs enhanced sensors. This exploit can also cause additional cost and work to the consumer, who starts wondering about the abnormally high CPU temperatures and starts troubleshooting the issue initially by remounting the cooling and usually, eventually by purchasing a better CPU cooler(s). While the 3700X SKU used in this example typically cannot even reach this kind of a power draw before running into the other limiters and limitations, the fact remains that the CPU is running far outside the spec without the user even acknowledging it. without enabling manual overclocking or AMD PBO). Also, it can cause issues when this exploit goes undetected by a hardware reviewer, since both the performance and the sofware based power consumption figures will be affected by it.įor example, if we take a Ryzen 7 3700X CPU that has 65W TDP and 88W default power limit (PPT), and use it on a board which has declared only 60% of its actual telemetry reference current, we'll end up with effective power limit of ~ 147W (88 / 0.6) despite running at stock settings (i.e. The issue with using this exploit is, that it messes up the power management of the CPU and potentially also decreases its lifespan because it is running the CPU outside the spec, in some cases by a vast margin. Since at least two of the largest motherboard manufacturers, still insist on using this exploit to gain an advantage over their competitors despite being constantly asked and told not to, we thought it would be only fair to allow the consumers to see if their boards are doing something they're not supposed to do. the CPU would think it consumes less power than it actually does. Likewise, if the declared value would be an understatement. In case the declared value is greater than the actual value, the power consumption seen by the CPU is greater than it actually is. In case the motherboard design specific, correct value differs greatly from the declared value, there will be a bias in the power consumption seen by the CPU. Because of that, it is on the motherboard manufacturers responsibility to find the correct value for their motherboard design through the means of calibration, and then to declare it properly in AGESA, during the bios compile time. The reference value mentioned earlier is generally different for each of the motherboard make and model, unless there are boards which have an identical power circuitry. Based on the accurately known current flow and the voltage, it is possible to calculate to CPU power draw in Watts (V * I). This means that the motherboard VRM controller will send an integer between 0 - 255 to the CPU, and based the reference value known by the co-processor firmwares, this integer is converted to a figure, that represents a physical current drawn by the CPU. The weakness of this method is, that the telemetry essentially uses an undefined scale for the current (and hence power) measurements. This information is consumed by the processors power management co-processor, that is responsible for adjusting the operating parameters of the CPU and ensuring, that neither the CPU SKU, platform or infrastructure specific limits are being violated. The voltage, current and power telemetry is provided to the processor by the motherboard VRM controller through the AMD SVI2 interface. ![]() Ryzen CPUs for AM4 platform rely on external, motherboard sourced telemetry to determine their power consumption.
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