ASRock B550M-ITX/ac — UEFI BIOS Reference (P2.20)
A field guide to every screen, setting, and value this board's BIOS has to offer — captured one photograph at a time. No recommendations here, just the territory.
Board: ASRock B550M-ITX/ac
UEFI version documented: P2.20
CPU at time of capture: AMD Ryzen 5 5600G with Radeon Graphics (3900MHz, microcode A50F00/A50000D)
RAM at time of capture: 2×8GB DDR4-3200 (dual channel, 16GB total)
License: This document is released into the public domain (CC0). Reproduce, fork, mirror, and adapt freely.
Status: Living document — capture in progress. Sections marked pending have not yet been photographed and documented.
How to read this document
Every setting below is listed with the value it held at the moment of capture on one specific board, plus whatever description text the BIOS itself provides (verbatim where short, paraphrased where the in-BIOS text ran long). Where the BIOS offers no help text, that's noted as such — it's a fact about the firmware, not an oversight in this document.
This is a description of what the UEFI setup utility contains, not advice on what any setting should be set to. Treat it the way you'd treat a dictionary: useful for knowing a word exists and what it means, not for deciding what to say with it.
Main
| Field |
Value |
| BIOS Version |
B550M-ITX/ac P2.20 |
| Processor Type |
AMD Ryzen 5 5600G with Radeon Graphics |
| Processor Speed |
3900MHz |
| Microcode Update |
A50F00/A50000D |
| Total Memory |
16GB |
| DDR4_A1 |
DDR4-3200 8GB |
| DDR4_B1 |
DDR4-3200 8GB |
OC Tweaker
| Setting |
Value |
Description |
| Overclock Mode (Bus Speed) |
Auto |
Select the overclock mode. Warning: when overclocking, the PCIe, PCI, SATA, and USB busses are overclocked too, which may cause instability or failure. Install an OS and required drivers before overclocking, or drives may become undetectable. Overclocking is not supported if the monitor is connected via the onboard D-Sub/VGA connector. |
| CPU Frequency and Voltage (VID) Change |
Auto |
If Manual, multiplier and voltage are set based on user selection. Final result depends on the CPU's capability. |
| SoC/Uncore OC Mode |
Auto |
AMD Overclocking Setup. Forces CPU SoC/uncore components (Infinity Fabric, memory, integrated graphics) to run at their maximum specified frequency at all times. May improve performance at the expense of idle power savings. |
| SoC/Uncore OC Voltage (VID) |
Auto |
— |
| CLDO VDDP Voltage Control |
Auto |
— |
| CLDO VDDG CCD Voltage Control |
Auto |
AMD Overclocking Setup. VDDG CCD represents voltage for the data portion of the Infinity Fabric. Derived from CPU SoC/Uncore Voltage (VDD_SOC). VDDG can approach but not exceed VDD_SOC. |
| CLDO VDDG IOD Voltage Control |
Auto |
— |
| DRAM Information |
(submenu) |
Browse the serial presence detect (SPD) for DDR4 modules. |
| DRAM Frequency |
DDR4-3200 |
If Auto, the motherboard detects installed memory module(s) and assigns the appropriate frequency automatically. Setting DRAM Frequency manually allows adjusting DRAM Timing. |
| 2.50V Voltage |
2.550V (display value) |
Configure the voltage for the 2.50V PROM Voltage. |
| Infinity Fabric Frequency and Dividers |
Auto |
— |
| DRAM Timing Configuration |
(submenu, not captured) |
— |
| External Voltage Settings and Load-Line Calibration |
(submenu, not captured) |
— |
| User Profile 1 |
[bigboy] |
Saved OC Tweaker profile slot |
| User Profile 2 |
Empty |
— |
| User Profile 3 |
Empty |
— |
Advanced
CPU Configuration
| Setting |
Value |
Description |
| Socket0 |
AMD Ryzen 5 5600G, 6 cores @ 3945MHz, 1350mV |
Read-only CPU identification |
| Processor Family / Model / CPUID |
19h / 50h–5Fh / 00A50F00 |
— |
| Max Speed |
3900 MHz |
— |
| L1/L2/L3 Cache |
32KB/8-way ×2, 512KB/8-way, 16MB total |
— |
| PSS Support |
Enabled |
Enable/disable generation of ACPI _PPC, _PSS, _PCT objects |
| NX Mode |
Enabled |
Enable/disable No-execute page protection |
| SVM Mode |
Enabled |
Enable/disable CPU Virtualization |
| SMT Mode |
Auto |
Disabling requires a power cycle to re-enable; S3 sleep is unsupported if SMT is disabled |
| AMD fTPM switch |
AMD CPU fTPM |
0 = AMD fTPM, 1 = Disabled, 2 = Onboard SPI TPM2.0 |
PCI Configuration
| Setting |
Value |
Description |
| Above 4G Decoding |
Enabled |
Globally enables 64-bit devices to decode in above-4G address space |
| Re-Size BAR Support |
Enabled |
Resizable BAR for capable PCIe devices |
| SR-IOV Support |
Disabled |
Single Root I/O Virtualization |
Onboard Devices Configuration
| Setting |
Value |
Description |
| Turn On Onboard LED in S5 |
Enabled |
Onboard LED behavior in ACPI S5 state |
| Restore Onboard LED Default |
Disabled |
— |
| RGB LED On/Off |
On |
— |
| HD Audio Controller |
Auto |
— |
| Front Panel |
HD |
Front panel audio type |
| Restore on AC/Power Loss |
Power Off |
Behavior after an AC power interruption |
| Onboard WAN/BT |
Enabled |
— |
| WAN Radio |
Enabled |
WiFi module connectivity |
| BT On/Off |
Auto |
— |
| Onboard LAN |
Enabled |
— |
| PS2 Y-Cable |
Auto |
— |
Storage Configuration
| Setting |
Value |
Description |
| SATA Mode |
AHCI |
Select SATA type |
| SATA Hot Plug |
Disabled |
— |
| SATA Port1–4, SATA M.2 |
All Not Present |
No drives connected at time of capture |
ACPI Configuration
| Setting |
Value |
Description |
| Suspend to RAM |
Auto |
ACPI S3 power-saving state |
| Deep Sleep |
Disabled |
ASRock's recommended default for compatibility/stability |
| PS/2 Keyboard S4/S5 Wakeup Support |
Disabled |
— |
| PCIE Devices Power On |
Disabled |
— |
| RTC Alarm Power On |
Disabled |
— |
Trusted Computing
| Field |
Value |
| Firmware Version |
3.84 |
| Vendor |
AMD |
| Security Device Support |
Enable |
| Active/Available PCR banks |
SHA-1, SHA256 |
| SHA-1 / SHA256 PCR Bank |
Enabled / Enabled |
| Pending operation |
None |
| Platform / Storage / Endorsement Hierarchy |
Enabled (all three) |
| TPM 2.0 UEFI Spec Version |
TCG_2 |
| Physical Presence Spec Version |
1.3 |
| TPM 2.0 InterfaceType |
CRB |
| Device Select |
Auto |
AMD PBS
| Setting |
Value |
Description |
| Primary Video Adaptor |
Ext Graphics (PEG) |
Selects which video output the board prioritizes |
| PCIe/GFX Lanes Configuration |
x16 |
Lane allocation to the primary PCIe graphics slot |
| PCIe x16 Bus Interface |
Auto |
— |
| NVMe RAID mode |
Disabled |
— |
| Adjust VddcrVddfull / VddcrSocfull Mode |
Auto / Auto |
— |
AMD Firmware Version (read-only):
AGESA ComboAM4v2PI 1.2.0.7 · PSP BootLoader/SecureOS 0.11.2.7B · ABL 23166070 · APCB 0030 · APOB 0018 · Ucode A50000D · SMU 0.64.61.0 · DXIO 55.774 · XHCI 0.0.0.1 · KVM 0.0.0 · VBIOS 13-CEZANNE-019 · GOP 2.18.0.17 · Chipset FW 210905900181
AMD Overclocking
| Item |
Value |
Note |
| Accept/Decline gate |
Accepted |
Standard liability disclaimer required to unlock the submenus below |
| Manual CPU Overclocking → Core control |
Auto |
All 6 cores active |
| Manual iGPU Overclocking → GFX Clock Frequency |
0 |
Inactive — needs both frequency and voltage set to take effect |
| Manual iGPU Overclocking → GFX Voltage |
0 |
Inactive |
| Precision Boost Overdrive |
Auto |
Defers to default boost behavior |
AMD CBS
The AMD CBS (Common BIOS Settings) menu is split into six top-level branches, each documented below.
CPU Common Options
| Setting |
Value |
Description |
| Core Performance Boost |
Auto |
"Disable CPB" toggle |
| Global C-state Control |
Disabled (factory default) |
Enable/disable CPU C-states |
| Fast Short REP MOVSB |
Enabled |
— |
| Enhanced REP MOVSB/STOSB |
Enabled |
— |
| IBS hardware workaround |
Auto |
For IBS execution sampling without software workaround for erratum 1.285 |
| Performance → Custom Core Pstates → Custom Pstate0 |
Auto |
Gated behind the same AMD warranty disclaimer pattern as AMD Overclocking |
| Prefetcher settings → L1 Stream HW Prefetcher |
Auto |
— |
| Prefetcher settings → L2 Stream HW Prefetcher |
Auto |
— |
DF Common Options
| Setting |
Value |
Description |
| Memory Addressing |
(submenu — see below) |
— |
| CC6 memory region encryption |
Auto |
Control whether CC6 save/restore memory is encrypted |
| Memory Clear |
Auto |
When disabled, BIOS does not implement MemClear after memory training (only relevant if non-ECC DIMMs are used) |
Sub-submenu: DF Common Options → Memory Addressing
| Setting |
Value |
Description |
| Memory interleaving |
Auto |
Allows disabling memory channel interleaving |
| Memory interleaving size |
Auto |
Valid values: Auto, 256 bytes, 512 bytes, 1 Kbytes, 2 Kbytes. Determines the starting address of the interleave (bit 8, 9, 10, or 11) |
| DRAM map inversion |
Auto |
Inverting the map causes the highest memory channels to be assigned the lowest addresses in the system |
UMC Common Options
| Setting |
Value |
Description |
| DDR4 Common Options |
(submenu — see below) |
— |
| DRAM Memory Mapping |
(submenu — see below) |
Memory Addressing |
Sub-submenu: UMC Common Options → DDR4 Common Options → Security
| Setting |
Value |
Description |
| TSME (Transparent SME) |
Disabled (factory default) |
No help string provided by BIOS |
Sub-submenu: UMC Common Options → DRAM Memory Mapping
| Setting |
Value |
Description |
| Chipselect Interleaving |
Auto |
Interleave memory blocks across the DRAM chip selects for node 0 |
| BankGroupSwap |
Auto |
No help string provided by BIOS |
| Address Hash Bank |
Auto |
Enable or disable bank address hashing |
| Address Hash CS |
Auto |
Enable or disable CS address hashing |
| Address Hash Rm |
Auto |
Enable or disable RM address hashing |
| SPD Read Optimization |
Enabled |
Enabled — SPD reads are skipped for reserved fields and most of the upper 256 bytes. Disabled — read all 512 SPD bytes. |
NBIO Common Options
| Setting |
Value |
Description |
| IOMMU |
Disabled (factory default) |
No help string provided by BIOS |
| PCIe ARI Support |
Disabled |
Enable/Disable ARI (Alternative Routing-ID Interpretation) |
| PCIe ARI Enumeration |
Auto |
No help string provided by BIOS |
| PSPP Policy |
Auto |
No help string provided by BIOS |
| GFX Configuration |
(submenu — see below) |
— |
| Audio Configuration |
(submenu — see below) |
Audio Configuration |
| SMU Common Options |
(submenu — see below) |
SMU Common Options |
Sub-submenu: NBIO Common Options → GFX Configuration
| Setting |
Value |
Description |
| iGPU Configuration |
Auto |
UMA Mode |
| GPU Host Translation Cache |
Auto |
Option to disable GPU Host Translation Cache |
Sub-submenu: NBIO Common Options → Audio Configuration
| Setting |
Value |
Description |
| NB Azalia |
Auto |
Enable Integrated HD Audio controller |
| Audio IOs |
Auto |
Audio IOs control |
| PDM Mic Selection |
Auto |
PDM Mic Selection |
Sub-submenu: NBIO Common Options → SMU Common Options
| Setting |
Value |
Description |
| STAPM Control |
(submenu — see below) |
— |
| SmartShift Control |
(submenu — see below) |
SmartShift Control |
| System Configuration AM4 |
Auto |
Warning text displayed on this field: "Select System Configuration may cause the system to hang, as some System Configuration may not be supported by your OPN." |
| CPPC |
(submenu — see below) |
CPPC |
Sub-submenu: SMU Common Options → STAPM Control
| Setting |
Value |
Description |
| STAPM Control |
Auto |
No help string provided by BIOS |
Sub-submenu: SMU Common Options → SmartShift Control
| Setting |
Value |
Description |
| SmartShift Control |
Auto |
No help string provided by BIOS |
Sub-submenu: SMU Common Options → CPPC
| Setting |
Value |
Description |
| CPPC CTRL |
Auto |
CPPC Control. Enable — Override. Disabled — Set default. |
| CPPC Preferred Cores |
Auto |
Enabled: CPPC highest-capability register of each thread will have a different value to express the AMD-recommended scheduling order to the OS. CPPC must be enabled for this parameter to have effect. Disabled: does not declare an AMD-preferred scheduling order to the OS. |
Soc Miscellaneous Control
| Setting |
Value |
Description |
| PSP RPMC Switch |
Auto |
Control RPMC usage. Enable: Enable RPMC function. Disable: Disable RPMC function. Auto: Keep default behavior. "This option is for test purpose only. NOT FOR PRODUCTION!!!" (on-screen warning, verbatim) |
| ABL Console Out Control |
Auto |
Enable: Enable ConsoleOut Function for ABL. Disable: Disable ConsoleOut Function for ABL. Auto: Keep default behavior. |
| ABL PMU message Control |
Auto |
Description not captured during this session |
Chipset Common Options
| Setting |
Value |
Description |
| SATA Configuration Options |
(submenu — see below) |
SATA Configuration Options |
| USB Configuration Options |
(submenu — see below) |
USB Configuration Options |
| USB Port Configuration Options |
(submenu — see below) |
USB Port Configuration Options |
Sub-submenu: Chipset Common Options → SATA Configuration Options
| Setting |
Value |
Description |
| SATA Mode |
Auto |
Select Promontory Plus SATA Type |
| Aggresive SATA Device Sleep Port 0 |
Auto |
No help string provided by BIOS |
| Aggresive SATA Device Sleep Port 1 |
Auto |
No help string provided by BIOS |
Sub-submenu: Chipset Common Options → USB Configuration Options
| Setting |
Value |
Description |
| XHCI GEN1 |
f |
Bit0–3 = 0 means original 5G port1 to port4 can be disabled and become USB 2.0 port |
| XHCI GEN2 |
0 |
Bit0–3 = 0 means original 10G port1 to port4 can be disabled and become 5G port |
| USB BT Remote Wakeup |
Auto |
Enable is only for HW PPON9 pin toggle reset |
Sub-submenu: Chipset Common Options → USB Port Configuration Options
| Setting |
Value |
Description |
| USB31 PORT0 |
Auto |
No help string provided by BIOS |
| USB31 PORT1 |
Auto |
No help string provided by BIOS |
| USB30 PORT0 |
Auto |
No help string provided by BIOS |
| USB30 PORT1 |
Auto |
No help string provided by BIOS |
| USB20 PORT0 |
Auto |
No help string provided by BIOS |
| USB20 PORT1 |
Auto |
No help string provided by BIOS |
| USB20 PORT2 |
Auto |
No help string provided by BIOS |
| USB20 PORT3 |
Auto |
No help string provided by BIOS |
| USB20 PORT4 |
Auto |
No help string provided by BIOS |
| USB20 PORT5 |
Auto |
No help string provided by BIOS |
Tool
A set of utility actions rather than configurable settings — each is invoked rather than set to a value.
| Item |
Description |
| RGB LED |
Submenu for onboard RGB lighting control (see below) |
| Easy RAID Installer |
Copies the RAID driver from the support CD to a USB storage device. After copying, the SATA mode must be changed to RAID before installing an OS in RAID mode. |
| SSD Secure Erase Tool |
Lists SSDs that support the Secure Erase function. At time of capture: SATA Controller (B:01 D:00 F:01) — no SSD found, or none of the attached SSDs support Secure Erase. |
| NVME Sanitization Tool |
After sanitizing, all user data on the NVMe SSD is permanently destroyed and cannot be recovered. No NVMe device was enumerated at time of capture. |
| Instant Flash |
Used to update the BIOS. UEFI files must be saved to a USB storage device formatted as FAT32/16/12, then loaded via this tool. On invocation, a notice dialog appears: "Please suspend BitLocker and any encryption or security relying on the TPM. Make sure that you have already stored and backed-up the recovery key. If the recovery key is missing while encryption is active, the data will stay encrypted and the system will not boot into the operating system. It is recommended to disable fTPM before updating the BIOS. Otherwise an unpredictable failure may occur." with Yes/No to continue. |
| Setting |
Value |
| LED Mode |
Rainbow |
| Speed |
128 |
| Brightness |
255 |
| Apply to all channel |
(action) |
| Save current data to MCU |
(action) |
H/W Monitor
Pending — not yet captured.
Security
| Setting |
Value |
Description |
| Supervisor Password |
Installed |
Set or change the password for the administrator account. Only the administrator has authority to change settings in the UEFI BIOS Setup Utility. Leave blank and press Enter to remove the password. |
| User Password |
Not Installed |
Set or change the password for the user account. Users are unable to change settings in the UEFI BIOS Setup Utility. Leave blank and press Enter to remove the password. |
| Password Check |
Setup |
Setup: check password when entering the UEFI Setup Utility. Always: check password on every boot. |
| Secure Boot |
(submenu, pending) |
Secure Boot configuration |
Boot
| Setting |
Value |
Description |
| Boot From Onboard LAN |
Disabled |
Boot From Onboard LAN |
| Setup Prompt Timeout |
10 |
Configure the number of seconds to wait for the UEFI BIOS setup utility |
| Fast Boot |
Disabled |
Fast Boot speeds up boot time, but disables booting from a USB storage device. Ultra Fast mode is supported by UEFI-aware OSes and requires a VBIOS supporting UEFI GOP if using an external graphics card; Ultra Fast mode boots so quickly that entering UEFI Setup requires a specific method (text on this field was truncated during capture). |
| Bootup Num-Lock |
On |
Select whether Num Lock is turned on or off when the system boots |
| Full Screen Logo |
Enabled |
Enable to display the boot logo, or disable to show normal POST messages |
| CSM (Compatibility Support Module) |
(submenu, pending) |
OpROM execution, boot options filter, etc. |
Exit
Pending — not yet captured.
Capture status
| Section |
Status |
| Main |
Complete |
| OC Tweaker |
Mostly complete — DRAM Timing Configuration and External Voltage Settings submenus not entered |
| Advanced → CPU/PCI/Onboard Devices/Storage/ACPI/Trusted Computing/AMD PBS/AMD Overclocking |
Complete |
| Advanced → AMD CBS (all six branches) |
Complete |
| Tool |
Complete |
| H/W Monitor |
Pending |
| Security |
Top level complete — Secure Boot submenu pending |
| Boot |
Top level complete — CSM submenu pending |
| Exit |
Pending |
Compiled from in-person UEFI photography across multiple sessions, June 2026. Public domain (CC0) — created by John A. Hoeven with the ethical assistance of Claude AI.
