I7 4790k - Prime95 High Temperatures ?? (H110)

DutchMike,

This is a widely known problem. As WildCard999 has already suggested, run only Prime95 version 26.6. Here's why:

2nd through 8th Generation i3, i5 and i7 CPU's have AVX (Advanced Vector Extension) Instruction Sets. Prime95 versions later than 26.6 run AVX code on the CPU's Floating Point Unit (FPU) which causes unrealistic temperatures up to 20°C higher due to excessively high TDP workloads.

Here’s a sample of utilities grouped as thermal and stability tests according to % of TDP, averaged across five Generations of processors at stock settings:

TDP ... Thermal Test - Steady Workload

129% ... Prime95 v27.7 through v29.4 - Small FFT’s (AVX, No Offset)
101% <-- Prime95 v26.6 - Small FFT’s
89% ... HeavyLoad v3.4.0.234 - Stress CPU
87% ... FurMark v1.19.1.0 - CPU Burner
78% ... CPU-Z v1.82.0 - Bench - Stress CPU
66% ... AIDA64 v5.95.4500 - System Stability Test - Stress CPU

TDP ... Stability Test - Fluctuating Workload (Peak)

123% ... OCCT v4.5.1 - CPU: OCCT (AVX, No Offset)
118% ... LinX v0.6.5 - Default
116% ... IntelBurn Test v2.54 - High
113% ... OCCT v4.5.1 - CPU: Linpack (AVX, No Offset)
110% ... AIDA64 v5.95.4500 - System Stability Test - Stress FPU
99% <-- Asus RealBench v2.56 - Stress Test (AVX, No Offset)
97% ... Intel Processor Diagnostic Tool v4.1.0.24 - Default
94% ... Sandra 2017.09.24.41 - Burn in - Processor Tests
92% ... CineBench v15.0 - CPU - Render Test
79% ... Intel Extreme Tuning Utility v6.4.1.15 - CPU Stress Test

All tests will show 100% CPU Utilization in Windows Task Manager, regardless of actual Workload. Higher TDP tests produce higher Core temperatures. Power (Watts) and Core temperatures will vary with Microarchitecture, Core count, Core speed, Core voltage, VID, Turbo Boost, Hyperthreading, Instruction Sets, Memory, IGPU, CPU cooler, BIOS versions and Microcode.

AVX can be disabled in Prime95 versions later than 26.6 by inserting "CpuSupportsAVX=0" into the "local.txt" file in Prime95's folder. However, since Core temperatures will be the same as 26.6, it's easier to just use 26.6.

Many 6th, 7th and 8th Generation motherboards address the AVX problem by providing offset adjustments in BIOS. However, motherboards that support 4th Generation processors do not have AVX offset adjustmets.

Download Prime95 and run only Small FFT's for just 10 minutes.

• Prime95 v26.6 - http://www.mersenneforum.org/showthread.php?t=15504

You might want to read this: Intel Temperature Guide - http://www.tomshardware.com/forum/id-1800828/intel-temperature-guide.html

CT