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Free & Open Source

HardWareDiag

Check used PC hardware before you buy — from AVITO, eBay, Craigslist, and other marketplaces. One tool for diagnostics, S.M.A.R.T., and stress tests.

10,000+ PCs checked
Open Source
4.8 ★ on GitHub

How it works

Three simple steps from download to informed decision.

1

Download

Get the app and bring it to the meetup on a USB stick or run from your laptop.

2

Run at the inspection

Launch HardWareDiag on the PC you're viewing. A few minutes — and you see real hardware state.

3

Learn the truth

Report: grade A–F, red flags, S.M.A.R.T. status. No more guessing — decide with facts.

What is HardWareDiag?

A free Windows app for buyers of used computers. Run it on a laptop or PC before or after purchase to see real hardware health: temperatures, disk S.M.A.R.T., RAM configuration, and an overall grade.

Dashboard
Dashboard
Diagnostics
Diagnostics
S.M.A.R.T.
S.M.A.R.T.
Stress tests
Stress tests

Features

Everything you need to make an informed purchase decision.

Full Hardware Info

CPU, GPU, RAM, disk & motherboard info with live temps and usage

Health Grade

Overall health grade (A–F) and red-flag detection

S.M.A.R.T. Analysis

Deep S.M.A.R.T. details for every disk

Stress Tests

CPU stress test, disk speed test, RAM check

Export Reports

Export report to PDF, copy to clipboard

7 Languages

7 languages: EN, RU, UA, FR, DE, SK, ZH

Open Source

Open source code — your guarantee of no viruses and miners. For system utilities this is critical.

View source on GitHub

For whom

Buyers of used PCs and laptops from classifieds and marketplaces — AVITO, eBay, Craigslist, Facebook Marketplace, Kleinanzeigen, Leboncoin, OLX and others. Also for home users and small offices who want to check their hardware health.

Where people buy used PCs

Popular marketplaces — open the one you use. Run HardWareDiag on the PC before or after purchase.

Buyer's checklist

What to look for when buying a used GPU (and PC)

  • Check GPU temperature at idle and under load — hidden overheating kills cards.
  • Run a stress test: artifacts or driver crashes mean trouble.
  • Check disk S.M.A.R.T. — reallocated or pending sectors mean the drive may fail soon.
  • RAM: same speed and capacity in both slots; dual channel for full performance.
  • Battery wear (laptops): over 20% wear means short battery life.
  • Power-on hours on the system drive — very high hours mean heavy past use.

Use HardWareDiag to check all of this in one go →

Normal inspection vs HardWareDiag

See the difference an informed inspection makes.

❌ Normal inspection ✅ With HardWareDiag
Visual / boot Looked at the case; turned it on — seems to work. Saw hidden memory chip overheating; grade D — walk away.
Disk No idea how much the drive was used. S.M.A.R.T. pre-failure, reallocated sectors — backup and replace.
RAM Seller says 16 GB. Mismatched speeds, single channel — real performance hit.
Trust Hope the seller is honest. Facts on screen — grade, red flags, export PDF for records.

Frequently Asked Questions

Is HardWareDiag really free?
Yes, completely free and open source. No ads, no premium version, no hidden fees. The source code is available on GitHub for anyone to audit.
Does it work on Mac or Linux?
Currently HardWareDiag is Windows only. Mac and Linux support may be added in the future. You can run it on your Windows laptop at the inspection meetup.
Do I need to install it?
No! The portable version (EXE) runs without installation. Put it on a USB stick and launch directly on the PC you're inspecting. There's also an installer if you prefer.
How long does a full check take?
A basic hardware scan takes 1–2 minutes. Running full stress tests and S.M.A.R.T. analysis may take 5–10 minutes depending on the system. You'll have a complete report with an A–F grade at the end.
Is my data safe?
HardWareDiag only reads hardware information — it never modifies, deletes, or uploads any of your data. Everything stays local on the machine. Open source means you can verify this yourself.