The i7-8700 struggles to reach over 3.8 GHz.
The i7-8700 struggles to reach over 3.8 GHz.
They won't. Drop the power cap. If things get too warm, you'll feel it. Even without realizing it, it will slow down to stay safe. It won't suddenly boost voltage to a dangerous level.
The default setting is Auto, have you adjusted it to 65? Otherwise, type "a" in the box and it will switch to Auto, but yes you can set it up to 255—it won’t affect watts, just lets the CPU boost according to Intel’s limits. Remember, this value reflects current performance, not power consumption.
You're not sure about the TDP value you're referring to—it's the "CPU Core/Cache Current Limit Max" in BIOS. There are other Intel settings for Boost performance, but this is the primary one. If adjusting any of those values, consider resetting BIOS or increasing them manually. Since everything remains stuck at Auto and the BIOS hasn't changed, it might be a bug; updating BIOS would be the best fix, as it should boost to 4.3GHz all-core by default.