"Full load" is a popular but
non-specific user term which could mean
anything, so it's important to be
very specific. Games, apps, streaming, rendering, transcoding and most utilities have partial,
fluctuating workloads with
fluctuating Core temperatures that are
not well suited for testing thermal performance.
“Stress” tests vary widely and can be characterized into two categories;
stability tests which are
fluctuating workloads, and
thermal tests which are
steady workloads. Prime95 v29.8 Small FFT's
(AVX disabled) is ideally suited for testing thermal performance, because it conforms to Intel's Datasheets as a
steady 100% workload with
steady Core temperatures. No other utility can so closely replicate Intel's thermal test workload.
Note: Click on the AVX test selections that are
not greyed out so that
all three AVX boxes are checked, as shown above.
Utilities that don't
overload or
underload your processor will give you a valid thermal baseline. Here’s a comparison of utilities grouped as
thermal and
stability tests according to % of TDP, averaged across six processor Generations at stock settings rounded to the nearest 5%:
Although these tests range from
70% to 130% TDP workload, Windows Task Manager interprets every test as
100% CPU Utilization, which is processor resource activity,
not actual workload.
Core temperatures respond directly to power consumption (Watts), which is driven by workload. Prime95 v29.8 Small FFT’s
(AVX disabled) provides a
steady 100% workload, even when TDP is exceeded by overclocking. If Core temperatures don't exceed
85°C, your CPU should run the most demanding
real-world workloads without overheating.
As per Intel’s Datasheets, TDP and Thermal Specifications are validated “without AVX”.
Concerning your question regarding "idle", since Windows has dozens of Processes and Services running in the background, rapid and random Core temperature “spikes” or fluctuations are
normal and
expected, especially during the first few minutes after startup.
Any software activity will show some percentage of CPU Utilization in Windows Task Manager, where unnecessary Tray items, Startups, Processes and Services that contribute to excessive spiking can be disabled.
6th Generation processors introduced "Speed Shift" technology in Windows 10, which responds much faster to changes in workload than "SpeedStep" due to having many more Core speed and Core voltage transition levels. This allows the processor to more rapidly complete brief tasks then quickly return to idle, which reduces overall power consumption and increases efficiency.
Since 7th through 9th Generation Speed Shift is twice as fast as 6th Generation, some users complain of Core temperature spikes which can also cause fluctuations in fan RPM at idle. Motherboard manufacturers have implemented BIOS updates that include separate SpeedStep and Speed Shift settings with more flexible fan curves and time delay options.
I suggest reading this:
Intel Temperature Guide
CT