We’re overclocking the Ryzen 9 5900 B2 CPU up to 5152 MHz in 5 minutes or less by Shaminocharging Precision Boost Overdrive using the ASUS ROG Crosshair VIII Extreme motherboard.

I’ll speed run you through the BIOS settings and provide some notes and tips along the way. Please note that this is for entertainment purposes only and most certainly not the whole picture. Please don’t outright copy these settings and apply to your system. If you want to learn how to overclock this system, please check out the longer SkatterBencher article.

Alright, let’s do this.

Ryzen 9 5900 B2 Overclock Settings

When you’ve entered the BIOS, go to the Extreme Tweaker menu.

Set Ai Overclock Tuner to D.O.C.P. Standard. This will make the memory run at our XMP rated DDR4-4266.

Set BCLK Frequency to 104.00. This will increase our Precision Boost algorithm frequencies by about 4%. So, if the algorithm sets 5000 MHz, the actual frequency will be 5200 MHz. Or, in our case, the maximum boost frequency ceiling goes up from 4950 MHz to 5148 MHz.

Set Memory Frequency to DDR-4229MHz. Because we increased the BCLK frequency by 4% our XMP rated frequency also increased by 4% to DDR4-4437. Since this is a bit too high we set a lower memory frequency.

Set Core Performance Boost to Enabled. This will ensure Precision Boost Overdrive is enabled while using a manual BCLK frequency

Enter the Precision Boost Overdrive submenu. Here’s where we’ll do most of the grunt work by tuning Precision Boost Overdrive

Set Precision Boost Overdrive to Manual.

Set PPT Limit to 205, TDC Limit to 150, and EDC Limit to 195. This increases the power, thermal, and current headroom of our motherboard VRM.

Set Precision Boost Overdrive Scalar to Manual and 10X. This tricks the PBO algorithm into thinking our CPU is much better than it actually is. So, it will push for higher voltages.

Enter the Curve Optimizer submenu and set Curve Optimizer to Per Core. Here’s where the real magic happens as curve optimizer allows us to adjust the V/f curve for each core by up to 30 steps of 3 to 5 mV. Setting a negative curve means the CPU will use less voltage for a given frequency. That in turn results in lower power, thermal, and current. This in turn gives more headroom for setting higher voltage. And that, well, that gives us higher frequencies.

I tested each core individually to find what’s the best Curve Optimizer setting.

• Set Core 0 to Core 11 Optimizer Sign to Negative
• Set Core 0 to Core 11, except Core 2, Curve Optimizer Magnitude to 30
• Set Core 2 Curve Optimizer Magnitude to 25

Leave the Curve Optimizer submenu

Set Max CPU Boost Clock Override to 200MHz. This increases the frequency ceiling by 200 MHz over the programmed max 1T limit. On the 5900 that’s 4750MHz even though the listed max boost frequency is 4700MHz. Adding 200 MHz results in a ceiling of 4950 MHz.

Leave the Precision Boost Overdrive submenu

Enter the External Digi+ Power Control submenu.

Set Core Voltage Suspension to Enabled. Voltage Suspension will force the CPU core voltage to stay within a specific range even when using a dynamic voltage like with Precision Boost Overdrive.

Set Co mitigator to 0.3. This helps mitigate system instability when using aggressive curve optimizer settings by boosting the voltage ever so slightly under very light loads.

Set Voltage Floor Mode to Dynamic. Dynamic mode allows us to configure a custom voltage temperature curve. This will make the target voltage range change based on the operating temperature. The Voltage floor is the lower bound for the target voltage

• Set Floor Low VMin to 1.15
• Set Floor Hot Temp to 90
• Set Floor High VMin to 1.40
• Set Floor Cold Temp to 60

Set Voltage Ceiling Mode to Dynamic. The voltage ceiling is the upper bound for the target voltage

• Set Ceiling Low VMax to 1.20
• Set Ceiling Hot Temp to 85
• Set Ceiling High VMax to 1.53125
• Set Ceiling Cold Temp to 65

Voltage suspension is effective up to 0.3V delta between requested voltage and target voltage. So, at a temperature of 65 degrees Celius the voltage ceiling is 1.53V. If the CPU requests 1.6V then the voltage will be 1.53V as the difference between both values is less than 0.3V and the ceiling is 1.53V.

Leave the External Digi+ Power Control submenu

Enter the Tweaker’s Paradise submenu

Set Force OC Mode Disable to Enabled. This will ensure manual OC Mode is disabled while using a manual BCLK frequency.

Leave the Tweaker’s Paradise submenu

Set CPU Core Voltage to Offset mode

Set offset Mode sign to +

Set CPU Core Voltage Offset to 0.075

Go to the Advanced menu

Enter the AMD CBS submenu

Enter the CPU Common Options submenu

Set Global C-State Control to Enabled. This will ensure proper frequency scaling when the BCLK frequency is over 101 MHz.

Then save and exit the BIOS.

Ryzen 9 5900 B2 Overclock Performance Improvement

To make sure everything is working as intended we re-run some benchmarks and check the performance increase compared to the default settings. Higher is better; and all are higher.

When running Prime 95 Small FFTs with AVX enabled, the average effective CPU clock is 4351 MHz with 1.200 volts. The average CPU temperature is 89 degrees Celsius and the average VRM temperature is 52 degrees Celsius. The average CPU package power is 213 watts.

When running Prime 95 Small FFTs with AVX disabled, the average effective CPU clock is 4455 MHz with 1.23 volts. The average CPU temperature is 84 degrees Celsius and the average VRM temperature is 51 degrees Celsius. The average CPU package power is 197 watts.

The highest Core Clock reported in the operating system is 5152 MHz. This is much higher than our adjusted frequency ceiling of 4950 MHz. When using the Corecycler application to check the effective clock frequency in a single threaded workload we find that the average peak effective clock in single threaded application across all cores is 4866 MHz.

And that’s it, thanks for reading and see you next time!