Do NOT run any versions of Prime95 later than 26.6. Here's why:
Core i 2nd, 3rd and 4th Generation CPU's have AVX (Advanced Vector Extension) instruction sets. Recent versions of Prime95, such as 28.5, run AVX code on the Floating Point Unit (FPU) math coprocessor, which produces extremely high temperatures. The FPU test in the stability testing utility AIDA64 shows the same results.
Prime95 v26.6 produces temperatures on 3rd and 4th Generation processors more consistent with 2nd Generation, which also have AVX instructions, but do not suffer from thermal extremes due to having a soldered Integrated Heat Spreader and a 35% larger Die.
Please download Prime95 version 26.6 - Windows Downloads Center: Prime95 26.6
Run only Small FFT’s for 10 minutes.
Use only Real Temp to measure your Core temperatures, as it was designed specifically for Intel processors: Real Temp - Download Real Temp | techPowerUp
Your Core temperatures will test 10 to 20C lower with v26.6 than with v28.5.