My Intel CPU is running too hot although my heatsink supports the specified TDP, what's the problem?

Current processors from Intel, especially the unlocked models with the suffixes C, K, X or XE (e.g. Core i7-8700K, Core i9-7900X oder Core i9-9900K) can dissipate noticeably more heat than indicated by the TDP specification.

While many motherboard models stick to the recommended power levels and clock speeds settings from Intel, there are models where the UEFI BIOS is configured in such a way that:

  1. the TDP limits are extended or disabled.
  2. the motherboard applies automatic overclocking by default, e.g. by raising the supply voltage of the CPU and using higher Turbo-Mode multipliers.

Depending on the load scenario and CPU configuration settings, the actual power draw can be 1.5-3 times as high the stated TDP value. This can lead to temperature issues, especially when using smaller coolers, compact cases or cases with poor airflow, when some applications create very high loads, e.g. Prime95 with AVX2 support, 3D-rendering or simulation software.

The actual power draw of the processor can be monitored with software provided by the motherboard vendor or with 3rd party tools like HWInfo or HWMonitor.

If you encounter temperature issues (>90°C) and notice a higher than specified power draw, please ensure that no automatic overclocking is applied. You might also want to limit the TDP to either the specified value by Intel or a value that is 5-10W below the value previously read out from the CPU. This can be done in BIOS by setting the “Long Term Duration Power” manually instead of “Auto”.

Furthermore, it may also help to lower the CPU clock speed for applications that heavily use the AVX instruction set, which can lead to higher loads and power draw. This option is usually referred to as “AVX offset” and makes it possible to lower the multiplier specifically for AVX based applications without reducing performance when using other instruction sets. Depending on the quality of the CPU and the programs being used, a reduction of 2-3 steps usually gives very good results.

The option to set an AVX-offset value is usually available for the following CPU generations:

  • LGA1151:7th, 8th and 9th generation (Kaby Lake, Coffee Lake)
  • LGA2011-3: 6th generation (Broadwell-E)
  • LGA2066: 7th and 8th generation (Skylake-X)

Please contact your motherboard vendor for details if you have trouble finding the appropriate settings in the BIOS.

All our TDP recommendations are based on thorough testing with the default values specified by Intel using popular applications such as Asus Realbench and prime95. Please note, however, that prime95 creates a particularly high load that goes beyond most typical application scenarios and this leads to elevated temperatures. We thus recommend using other programs such as Realbench for checking the stability and temperatures of the CPU in realistic scenarios.

Please also note that CPUs that use thermal paste instead of soldering between the DIE and the heatspreader generally run hotter. Due to the thermal bottleneck created by the thermal paste, temperatures can be high even at the specified TDP.

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