Dell Precision 5570 — CPU Throttle Fix + ThrottleStop Setup

Hardware: Dell Precision 5570, Intel i7-12700H, NVIDIA RTX A2000 8GB
Problem: CPU throttled to ~400 MHz when using non-Dell USB-C charger
Root cause: Dell EC detects non-original charger via USB-C CC authentication (CCG6 chip), asserts BD PROCHOT hardware pin → CPU throttles. PROCHOT Lock in UEFI NVRAM prevents ThrottleStop from disabling this at runtime.
Solution: Unlock PROCHOT Lock in UEFI NVRAM via GRUB shell, then configure ThrottleStop to disable BD PROCHOT input permanently.

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Quick Start (after fresh install)

# 1. Do Part 1 (UEFI unlock) — one time only, survives reboots
# 2. Copy ThrottleStop to any folder
# 3. Run as Administrator:
powershell -ExecutionPolicy Bypass -File install.ps1
# 4. Open ThrottleStop → Profile 1 (AC Max) → UNCHECK "BD PROCHOT" → TURN ON

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Part 1 — Unlock PROCHOT Lock in UEFI NVRAM

What gets unlocked

NVRAM variable CpuSetup (GUID B08F97FF-E6E8-4193-A997-5E9E9B0ADB32):

Offset	Name	Locked	Unlocked
0x0E	OC Lock	0x01	0x00
0x43	CFG Lock	0x01	0x00
0x7D	PROCHOT Lock	0x01	0x00

This is a one-time operation. Settings survive reboots but are reset by BIOS updates.

Requirements

modGRUBShell.efi v1.4+

Option A — Boot from USB drive

1. Format USB as FAT32
2. Place modGRUBShell.efi at \EFI\BOOT\BOOTX64.EFI
3. Boot from USB via F12 at POST

Option B — Boot from EFI System Partition (already set up on this machine)

# Run as Administrator in Windows:
bcdedit /set "{fwbootmgr}" bootsequence "{968ae6f8-f0fd-11ef-b49d-b3dae714c264}"
shutdown /r /fw /t 0

The GUID above is specific to this machine's EFI entry for modGRUBShell. On a different machine, register the entry first via bcdedit /copy or EasyUEFI.

GRUB shell commands

At the grub> prompt:

setup_var_cv CpuSetup 0x0E 0x01 0x00
setup_var_cv CpuSetup 0x43 0x01 0x00
setup_var_cv CpuSetup 0x7D 0x01 0x00
reboot

Each command prints old: 0x01 new: 0x00 on success.

Verify (Windows, run as Administrator)

python tools\read_cpusetup.py

Results are written to tools\read_cpusetup_output.txt.
All three offsets should show 0x00 (UNLOCKED).

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Part 2 — ThrottleStop + Auto-Switching Setup

Install (run as Administrator)

powershell -ExecutionPolicy Bypass -File install.ps1

install.ps1 does everything automatically:

• Copies on_power_change.ps1 and start_ts_minimized.ps1 into the ThrottleStop folder
• Deploys configs\ThrottleStop.ini (power limits, lock settings) into the ThrottleStop folder
• Reports the detected NVIDIA discrete GPU device ID (detection runs at runtime, no patching needed)
• Fixes profile names in ThrottleStop.ini
• Creates two scheduled tasks: PowerSourceChange and ThrottleStop (logon)

If ThrottleStop.exe is not found automatically:

powershell -ExecutionPolicy Bypass -File install.ps1 -ThrottleStopDir "C:\path\to\ThrottleStop"

ThrottleStop profiles

Profile	INI index	Name	Trigger
1	0	AC Max	Charger connected
4	3	Battery ECO	Running on battery

After install, open ThrottleStop and in Profile 1 (AC Max) uncheck the "BD PROCHOT" checkbox.
The checkbox reflects the current hardware state: checked = BD PROCHOT active (CPU throttles on external signal), unchecked = disabled. Before the UEFI unlock the checkbox is greyed out and checked (locked on) — Part 1 unlocks the MSR so ThrottleStop can clear it.
After correctly unchecking it, ThrottleStop 9.7 automatically re-locks the MSR to prevent other software from re-enabling it — the checkbox becomes greyed out and unchecked. This is correct and expected.
If the checkbox is greyed out and checked, PROCHOT Lock is still set in NVRAM (Part 1 not done).

Power limits (TPL)

Open ThrottleStop → TPL button and set the following, then click Apply → OK → TURN ON:

	AC Max (Profile 1)	Battery ECO (Profile 4)
PL1 (sustained)	65W	28W
PL2 (burst)	115W	45W
Time window	28 sec	28 sec
Lock	yes	yes

PL1 is the sustained power limit. PL2 is the short-term burst limit — the CPU runs at PL2 until the sliding average over the Time window reaches PL1, then drops back to PL1. Lock prevents Windows and Intel DTT from overwriting the limits.

These values are already set in configs\ThrottleStop.ini — if you load the config in ThrottleStop it will populate the fields automatically.

Preventing conflicts with Intel DTT

Windows ships with Intel Innovation Platform Framework (IPF/DTT) which dynamically adjusts CPU and GPU power limits and can overwrite ThrottleStop settings. With Lock enabled in TPL, ThrottleStop sets the MSR lock bit on every profile switch — DTT cannot write CPU power limits while the lock is active.

Optionally, set the Windows High Performance power plan to prevent ACPI from frequency-scaling the CPU independently:

# Run as Administrator
powercfg /setactive 8c5e7fda-e8bf-4a96-9a85-a6e23a8c635c

How auto-switching works

• Windows fires Kernel-Power Event ID 105 on every AC plug/unplug
• Scheduled task PowerSourceChange runs on_power_change.ps1 with admin rights
• Script reads actual AC state at runtime:
  • AC plugged: enable NVIDIA GPU → switch to Profile 1 (AC Max)
  • Battery: switch to Profile 4 (Battery ECO) → disable NVIDIA GPU

Log: power_monitor.log in the ThrottleStop folder.

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File Reference

precision-5570-setup\
├── README.md                    — this file
├── install.ps1                  — run as Admin to set everything up
├── scripts\
│   ├── on_power_change.ps1      — AC/battery switch (event-triggered, NVIDIA auto-detected)
│   └── start_ts_minimized.ps1   — starts ThrottleStop minimized at logon
├── configs\
│   └── ThrottleStop.ini         — full config with power limits for all profiles
├── docs\
│   └── battery-controller-protocol.md  — Dell DDV WMI, ACPI WMDV commands, charge thresholds
└── tools\
    └── read_cpusetup.py         — reads CpuSetup NVRAM, prints lock status

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Troubleshooting

BD PROCHOT checkbox is greyed out and unchecked
→ This is correct. ThrottleStop 9.7 locked the MSR after disabling BD PROCHOT — no action needed.

BD PROCHOT checkbox is greyed out and checked
→ PROCHOT Lock is still set in NVRAM. Redo Part 1, verify with read_cpusetup.py.

Switching doesn't fire on charger plug/unplug
→ Check task status: schtasks /query /tn "PowerSourceChange" /fo LIST
→ Re-run install.ps1 as Administrator.
→ Check power_monitor.log in the ThrottleStop folder.

ThrottleStop opens as a window instead of minimized
→ Re-run install.ps1 as Administrator (updates logon task).

After BIOS update, throttling returns
→ BIOS updates reset NVRAM. Redo Part 1 (GRUB unlock).
→ Uncheck BD PROCHOT in Profile 1 again after reboot.

Need to check lock status without rebooting
→ python tools\read_cpusetup.py as Administrator → see read_cpusetup_output.txt.