These temperatures seem safe.
These temperatures seem safe.
I'm using an i5 4690k at 4.2ghz with a boost frequency of 1.23v. Running prime95 it will get close to 75 degrees, is this safe for the 4690k? Should I lower the frequency?
My i5 4690K operates smoothly at 4.6Ghz with a voltage of 1.283V, maintaining temperatures near 80C using Prime95 26.6. It stays around 32C during idle and seldom reaches 60C during regular gaming sessions. When pushing the CPU to its limits, it's likely safe for a short time to reach 80C. For your chip, I'd consider increasing the voltage and multiplier, aiming for at least 4.4 Ghz.
Thermal Junction max reaches 105°C. THERMALTRIP activates near 115°C. Which prime95 version are you using? Please ensure you're running the newest one, since it checks your stability with Advanced Vector Extension and Fused Multiplication Addition instruction sets. Many users try version 26.6, but it doesn't fully assess your CPU's true stability or performance beyond its specifications.