What software would allow me to compare 2 x SD cards to ensure image on both is exactly the same?

There are a few solid ways to do this, depending on how “exact” you want the comparison to be (file-level vs full raw image comparison). For SD cards, you usually want byte-for-byte verification.

🔧 Best approach (recommended)

1) Image both cards, then compare hashes

• Use something like Win32 Disk Imager
• Read each SD card into an .img file
• Then compare the two image files using a hash (SHA-256)

Why this works:

• It compares every byte including boot sectors and unused space
• The tool can even verify the written image automatically

For hashing:

• Use DeadHash (simple GUI)
• Or command line tools (e.g. sha256sum)

If the hashes match → the cards are identical bit-for-bit

🔬 More advanced / forensic comparison

2) Deep comparison

• Use diffoscope
• It can compare disk images and show exact differences

Best if:

• You suspect subtle differences
• You want to see what changed, not just “same/different”

📂 File-level comparison (less strict)

3) Compare contents only

• Tools like Jacksum or CRC-based utilities
• Compare all files via checksums

Useful if:

• You only care about files, not boot sectors or partition layout

But note:

• This will NOT guarantee identical images (e.g. partition tables could differ)

🧠 Practical summary

• Best overall: Image → hash compare (simple + definitive)
• For diagnostics: diffoscope
• For quick checks: file-level hash tools

⚡ Quick workflow (what I’d actually do)

1. Read SD card A → A.img
2. Read SD card B → B.img
3. Run:sha256sum A.img sha256sum B.img
4. Compare hashes

If identical → you’re done.

Windows comparing Raspberry PI images:-

On Windows, comparing two Raspberry Pi SD cards properly (bit-for-bit) is straightforward if you follow a clean imaging + hashing workflow.

🥇 Easiest reliable method (what you want)

Step 1 — Create images of both cards

Use Win32 Disk Imager

• Insert SD card A
• Read → save as cardA.img
• Insert SD card B
• Read → save as cardB.img

This captures everything (boot sector, partitions, unused space).

Step 2 — Compare with hashes

Use DeadHash (simple GUI)

• Open both .img files
• Select SHA-256
• Generate hashes

👉 If the hashes match → the cards are 100% identical bit-for-bit
👉 If they differ → something is different somewhere

⚡ Faster command-line option (no extra installs)

Windows has a built-in tool:

certutil -hashfile cardA.img SHA256
certutil -hashfile cardB.img SHA256

Compare the outputs manually.

🔬 If you want to see what’s different

Use diffoscope

• It can compare the two .img files
• Shows exact differences (files, partitions, metadata)

⚠️ Important Raspberry Pi gotcha

Even if you cloned one card to another, differences can appear due to:

• Different SD card sizes (even “same size” brands vary slightly)
• Filesystem auto-expansion on first boot
• Timestamps/log files changing

So:

• If hashes differ, it doesn’t always mean a problem
• But if hashes match → you can be absolutely certain they’re identical

🧠 Practical tip

If your goal is just to confirm a successful clone:

• Use Win32 Disk Imager’s built-in “Verify” option right after writing
• That’s the quickest “yes/no” check without manual hashing