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Processor - Intel® Core™ i5-8265U Processor

CPU-Z shows 0.6XX - 1.1XX (depending on energy mode) for core VID changing constantly, a few times in second, the core speed also changes, this is also in idle.

Video - https://streamable.com/ymgtt6

Compared to Intel Celeron laptop, core VID and speed change there as well but way more stable.

OS: Windows 10 Pro RAM: 8GB SSD: 256 NVME

NOTE: vcore (originally in the qn) was changed to core VID.

UPDATE: Checking other CPUs with similar technologies i5 7th series, i5 8250 fluctuations of VID are very similar, and due to (most probably) TurboBoost, speed shift and SpeedStep techs (see link below).

https://ark.intel.com/content/www/us/en/ark/products/149088/intel-core-i5-8265u-processor-6m-cache-up-to-3-90-ghz.html

Advanced Technologies

Intel® Optane™ Memory Supported ‡ Yes
**Intel® Speed Shift Technology Yes**
**Intel® Turbo Boost Technology ‡ 2.0**
Intel® vPro™ Platform Eligibility ‡ No
Intel® Hyper-Threading Technology ‡ Yes
Intel® Virtualization Technology (VT-x) ‡ Yes
Intel® Virtualization Technology for Directed I/O (VT-d) ‡ Yes
Intel® VT-x with Extended Page Tables (EPT) ‡ Yes
Intel® Transactional Synchronization Extensions No
Intel® 64 ‡ Yes
Instruction Set 64-bit
Instruction Set Extensions Intel® SSE4.1, Intel® SSE4.2, Intel® AVX2
Intel® My WiFi Technology Yes
**Idle States Yes**
**Enhanced Intel SpeedStep® Technology Yes**
Thermal Monitoring Technologies Yes
Intel® Flex Memory Access Yes
Intel® Identity Protection Technology ‡ Yes
Intel® Stable Image Platform Program (SIPP) No
Intel® Smart Response Technology Yes
Vitaliy Terziev
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1 Answers1

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This is DVFS (or Dynamic Frequency Scaling / Dynamic Voltage Scaling), and it is very likely that it is operating correctly - if it wasn't you'd see either instability, or excess heat and reduced battery life.

You're not looking for stability here, but rather "lowest power state" vs. "best performance", depending on what the system is trying to do...

  • Reducing the core voltage will make the CPU consume less power (Watts), but it will also mean that it becomes unstable at higher frequencies (speeds), so the frequency will be reduced, and performance will drop with it.
  • Increasing the core voltage will make the CPU consume more power, and will permit it to remain stable at higher frequencies, allowing the frequency to be increased, and additional performance to be realised.

If you're just browsing test-based websites like Super User, then aside from the sporadic HTTP requests and page rendering you may be asking for, your computer can be almost 100% idle, and during this time, it makes a lot of sense to reduce its power consumption.

DVFS is presented under different trade names, for example Intel's SpeedStep and Turbo Boost, or AMD's PowerTune and Turbo Core. Technologies like Turbo Boost will actually overclock your CPU for you when possible (based on demand and thermal headroom), adjusting the parameters multiple times per second to carefully balance power consumption vs. performance.

The ark.intel.com page for your processor lists certain specifications, including: (sorted by me)

  • Intel Turbo Boost Frequency: 3.90 GHz (i.e: highest peak frequency)
  • Configurable TDP-up Frequency: 1.80 GHz (i.e: highest constant frequency)
  • Configurable TDP-up (Power / Watts): 25 W
  • Processor Base Frequency: 1.60 GHz
  • Configurable TDP-down Frequency: 800 MHz
  • Configurable TDP-down (Power / Watts): 10 W

It's actually beneficial for this core voltage and frequency configuration to be quite agile, as it's possible to return to a lower power state more quickly once the workload has been cleared. Equally, it's possible to step up to a high performance state when new work comes in.

The "Core VID" field you've asked about and shown in your screenshot is actually a "request voltage", not a measurement - the processor is requesting that the motherboard configures its VCORE power supply to 0.665v (for example).

Once the motherboard's power supply is reconfigured (presuming you've not manually overriden the processor's request, i.e: if you're overclocking), it should then supply the requested voltage to the CPU package.

A number of things can affect the voltage that is actually received by the CPU die itself, such as the size and length of the copper power planes on the motherboard. Remember, ignoring the Turbo Boost, we might be talking about ~18-20 Amps here (25W / ~1.35v), which is considerable, even for a "low power" CPU like the i5-8265U.

Depending on where the voltage is measured (i.e: close to power supply, or close to socket, or on-die) can have a relatively significant impact on the figures (I've seen 10-20% error quoted)... it may not even be measured and made available to software at all.

Attie
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