Raspberry Pi Overclocking Guide

Introduction

Overclocking can boost performance by 15–30% on Raspberry Pi 4 and 5, useful for running heavier workloads. This guide covers safe settings, cooling requirements, stability testing, and when to skip overclocking entirely.

Prerequisites

• Raspberry Pi 4 or Pi 5
• Adequate cooling (heatsink minimum, fan recommended)
• SSH access or terminal
• stress-ng for stability testing
• Backup of current /boot/config.txt

Step 1 — Backup and Prepare

Always back up before modifying boot config:

sudo cp /boot/firmware/config.txt /boot/firmware/config.txt.backup

On older Raspbian (before May 2023), the path is /boot/config.txt. Check your Pi's boot location:

ls -la /boot/

Step 2 — Overclock Settings by Model

Edit the config file:

sudo nano /boot/firmware/config.txt

Add or modify these lines at the end:

Raspberry Pi 4 (Conservative, Daily Use)

[pi4]
arm_freq=1950
arm_voltage=4
gpu_freq=600
over_voltage=2
force_turbo=0

Raspberry Pi 4 (Aggressive, Heavy Workload)

[pi4]
arm_freq=2000
arm_voltage=6
gpu_freq=650
over_voltage=4
force_turbo=1

Raspberry Pi 5 (Safe, No Derating)

[pi5]
arm_freq=3000
gpu_freq=910
over_voltage=0

The Pi 5's new firmware handles thermal throttling gracefully—it won't crash. Even with arm_freq=3000, voltage stays stable at stock.

Settings Reference

Parameter	Effect	Safe Range
arm_freq	CPU frequency (MHz)	Pi 4: 1800–2100; Pi 5: 2800–3200
gpu_freq	GPU frequency (MHz)	Pi 4: 500–700; Pi 5: 850–1000
over_voltage	Increase voltage (steps of 0.025V)	Pi 4: 0–6; Pi 5: 0–2
arm_voltage	Set CPU voltage directly	Pi 4: 1.2–1.3V (recorded as 0–8 offset)
force_turbo	Always run at max frequency	0 (adaptive) or 1 (always on)

Higher over_voltage cuts lifespan. Limit to 2–4 on Pi 4 for longevity.

Step 3 — Set Up Cooling

Overclocking without cooling throttles immediately. Upgrade your thermal management:

Passive (Heatsink only)

• Cost: $5–15
• Performance: 5–10°C drop
• Best for: Pi running at stock or mild 1950 MHz

Active (Small fan + heatsink)

• Cost: $15–30
• Performance: 15–25°C drop
• Best for: Daily overclocking to 1950–2000 MHz

High-end (Ice Tower or equivalent)

• Cost: $40–70
• Performance: 25–35°C drop
• Best for: 2000+ MHz, sustained loads

Install a heatsink with thermal pads—no thermal paste needed. Verify contact with vcgencmd measure_temp before and after overclocking.

Step 4 — Stability Testing

After setting overclock, stress-test for 30+ minutes:

# Install stress-ng
sudo apt install stress-ng -y

# Run CPU stress test for 30 minutes
stress-ng --cpu 4 --timeout 30m --metrics-brief

# During test, monitor temperature in another terminal
watch -n 1 'vcgencmd measure_temp'

Good result: Sustained performance, temp stays <80°C, no crashes.

Bad result: Throttling kicks in (freq drops), crashes, or thermal shutdown. Revert to previous settings or add cooling.

Check for errors:

# See system messages
dmesg | tail -20

Look for CPU voltage warnings or thermal_cstate messages—these indicate instability.

Step 5 — Benchmark Before and After

Measure real-world impact with Sysbench:

# Install sysbench
sudo apt install sysbench -y

# Single-thread CPU benchmark (no overclock baseline first)
sysbench cpu --cpu-total-threads=1 run

# Multi-thread
sysbench cpu --cpu-total-threads=4 run

Typical results (Pi 4, stock vs overclocked 2000 MHz):

• Single-thread: 1200 → 1500 events/sec (+25%)
• Multi-thread: 4000 → 5500 events/sec (+37%)

Warranty and When NOT to Overclock

Voids warranty? Overvolting does. Check your Pi's fuse:

vcgencmd read_register 0x3d5812d0

If it returns a non-zero value, you've triggered the overvolt fuse and voided the warranty. Stock frequency changes alone don't trigger it.

Skip overclocking if:

• Running at 80+ °C already without overclock
• Using Pi in a sealed enclosure
• Deployed remotely and can't monitor it
• Running 24/7 on battery—extra power draw drains it faster

Troubleshooting

Pi won't boot after overclock This is why you backed up config.txt. Boot into recovery:

sudo cp /boot/firmware/config.txt.backup /boot/firmware/config.txt
sudo reboot

Temperature stuck high (>85°C) Your cooler isn't making contact. Remove and reapply thermal pad, ensuring heatsink sits flush. Test with heatsink only (no fan) to isolate the issue.

Crashes under load, stable at rest Reduce arm_freq or over_voltage by one notch. Pi 4 is usually stable at 1950 MHz with voltage 2–4; pushing to 2000 MHz requires voltage 4–6.

Thermal throttling kicks in mid-test GPU is competing for cooling. Reduce gpu_freq or improve air flow. Pi 5 handles this better with dynamic thermal management.

Summary

Conservative overclocking (Pi 4 to 1950 MHz, Pi 5 to 3000 MHz) with passive cooling adds noticeable performance for demanding workloads. Test thoroughly and monitor temps—the 20–30% speed gain isn't worth a dead Pi. For production deployments, keep stock settings and invest in better code optimization instead.