ferritest

A quick memory sanity check for modders. Before you spend hours debugging a crash, rule out bad RAM in under a minute.

The name combines "ferrite" (a nod to ferrite core memory) with "test".

Why This Exists

Modding toolchains are complex. When something crashes, it could be:

• A bad mod
• A load order conflict
• An outdated plugin
• ...or just faulty RAM silently corrupting data

ferritest lets you quickly rule out memory as the culprit. Run it before diving into mod conflict debugging. If it passes, your RAM is fine and you can focus on the actual problem.

Quick Start

Download the latest release for your platform from Releases.

# Quick 1GB test (under a minute)
ferritest

# More thorough 4GB test
ferritest -m 4096

# Let it run while you grab coffee
ferritest -m 8192 -d 10m

If you see SUCCESS: No memory errors detected! - your RAM is fine. Move on to debugging your mods.

Installation

Download Binary

Grab the latest release for your platform:

• Windows: ferritest-windows-x64.zip
• macOS (Intel): ferritest-macos-x64.tar.gz
• macOS (Apple Silicon): ferritest-macos-arm64.tar.gz
• Linux: ferritest-linux-x64.tar.gz

From crates.io

cargo install ferritest

From source

git clone https://github.com/ezmode-games/ferritest.git
cd ferritest
cargo build --release

Building Without GPU Support

GPU support is enabled by default. To build a smaller binary without GPU support:

cargo build --release --no-default-features

Usage Examples

# Basic test (1 GB, single pass)
ferritest

# Test 4 GB of RAM
ferritest -m 4096

# Run for 10 minutes
ferritest -d 10m

# Run continuously until error or Ctrl+C
ferritest --continuous

# Use specific number of threads
ferritest -t 8

# Thorough overnight test
ferritest -m 16384 --continuous

GPU Memory Testing

ferritest can also test your GPU's video memory (VRAM) using compute shaders with the same patterns.

GPU Quick Start

# List available GPUs
ferritest --list-gpus

# Test default GPU (1GB VRAM)
ferritest --gpu

# Test 4GB of VRAM
ferritest --gpu -m 4096

# Test specific GPU by index
ferritest --gpu --gpu-index 1

# Test all GPUs sequentially
ferritest --gpu --gpu-index all

Platform Support

Platform	GPU Backend
Windows	DirectX 12, Vulkan
macOS	Metal
Linux	Vulkan

GPU Limitations

• Cannot test 100% of VRAM (driver/OS reserves memory)
• Requires compatible GPU with Vulkan/Metal/DX12 support
• GPU tests may be slower than CPU due to readback latency

Command Line Options

General Options

Option	Description
-m, --memory-mb <MB>	Amount of memory to test (default: 1024)
-d, --duration <TIME>	How long to run (e.g., '5m', '1h', 'infinite')
-t, --threads <NUM>	Number of threads (default: all CPU cores)
--continuous	Run until error or Ctrl+C
-v, --verbose	Verbose output
-h, --help	Show help

GPU Options

Option	Description
--gpu	Enable GPU VRAM testing instead of CPU RAM
--gpu-index <N|all>	Select GPU by index or test all GPUs
--list-gpus	Show available GPUs and exit
--gpu-timeout <SECS>	Per-operation timeout (default: 30)

What It Tests

8 different patterns catch various types of memory errors:

Pattern	What It Catches
Walking Ones	Stuck-at-zero faults
Walking Zeros	Stuck-at-one faults
Checkerboard	Adjacent cell interference
Inverse Checkerboard	Coupling faults
Random	General data retention
All Zeros	Basic write/read
All Ones	Basic write/read
Sequential	Address line faults

Example Output

Memory Stress Test
==================
Memory to test: 1024 MB (requested: 1024 MB)
Block size: 64 MB
Threads: 16
Blocks per thread: 1
Mode: Single pass

Elapsed: 45.2s | Tested: 8192 MB | Speed: 181.23 MB/s | Tests: 128 | Errors: 0

Test Complete
=============
Total bytes tested: 8192 MB
Total tests completed: 128
Errors found: 0
Duration: 45.23s

SUCCESS: No memory errors detected!

Exit Codes

• 0: No errors detected
• 1: Memory errors found

Useful for scripting: ferritest && echo "RAM OK" || echo "RAM BAD"

Limitations

• Tests user-space memory only (not kernel/reserved)
• For thorough hardware testing, use memtest86+ (bootable)
• Results depend on OS memory allocation

Technical Details

CPU Testing

• Multi-threaded (uses all CPU cores by default)
• 64 MB block size for optimal cache behavior
• Lock-free statistics via Arc<AtomicU64>
• Zero unsafe code

GPU Testing

• Cross-platform via wgpu (Vulkan/Metal/DX12)
• WGSL compute shaders for pattern generation and verification
• Atomic error counting on GPU
• Staging buffer for error readback

License

MIT

Part of ezmode.games

Built for the modding community. Check out our other tools at ezmode.games.