The i9-9900K no longer supports speeds up to 5GHz.
The i9-9900K no longer supports speeds up to 5GHz.
It's the combination of timing, luck, and a bit of strategy that led you to this outcome.
To reach the 50 multiplier, activate at least one core C State (C3 - C6 - C7) in the bios.
I attempted but nothing altered. I tried only one or a mix of the C settings. They sent them back to Auto (also thought of as "Enabled"). Occasionally I see x49 multiplier, but never when under load. All loads cause them to drop to x47.
Operating normally is expected. In Windows you won’t typically notice the x50 multiplier with turbo boost, and the x49 multiplier rarely appears during load. The task scheduler frequently switches tasks across threads, along with background processes running on multiple threads, which can disrupt turbo boost. Using Throttlestop 8.70+ to track clock speeds (instead of HWinfo64) and enabling "More data" might help you observe x49 or x50 more often. I believe HWinfo64 updates slower than 250ms per poll. For seeing higher ratios at lower loads, running a Linux environment would be necessary.
It's interesting how little you know about this beforehand. Just log in and express your gratitude! I experimented with negative offset voltage on my stock 9900K + Z370 Taichi, but it caused freezing when idle. Someone mentioned disabling C3, C6, and C7 resolved the problem, so I tried that and it worked. Then I missed checking the clock speed for a couple of days, which made me curious why my 9900K can't go beyond 4.7GHz anymore. I came across a post but still have doubts about handling idle freezes if I enable C3. I'm testing C3 auto instead of enabling or disabling and just waiting to see the results.
C3 appears to be working well so far (C6 and C7 remain off). I own this CPU for about six months now. Before this, I boosted it to 5Ghz with a fixed voltage of 1.29V. Under heavy load, the VR VOUT stays at 1.22V, while gaming or idle gives 1.26-1.27V. My ASRock doesn't support adaptive voltage control, so I'm using only fixed, offset, auto, and negative offset settings to conserve power during idle. Here are my current configurations for the 9900K and Z370 Taichi: CPU Ratio = auto, MCE = on, Voltage = -70mV offset, LLC auto (level 4). C3 = auto, C6/C7 = disabled, rest features enabled. Windows power plan is set to power-saving mode. I observe that this setting can push VR VOUT down to around 0.6V during idle more often than balance or performance modes.