9 Best Windows Diagnostic and Hardware Tools in 2026

Diagnosing a PC problem is a sequence, and most people run it in the wrong order — installing a cleanup tool before they know what the hardware is.

The correct order is:

1. Identify. What is actually in this machine? Not what the box said — what the silicon reports. CPU-Z, GPU-Z.

2. Measure. How hot does it run, and what are the voltages doing under load? HWMonitor.

3. Look at the disk. Because "the drive is full" is the single most common cause of a slow Windows machine. TreeSize.

4. Look at the network. When the problem is not the machine at all. Wireshark.

5. Fix the drivers. Usually last, and usually with DDU rather than a driver updater.

Six of these nine tools are under 13 MB, which is a good sign in this category: a diagnostic tool should be small, focused and boring.

Every version, size, minimum Windows and licence below is the catalogue entry for the package this site serves.

Identify the hardware

1. CPU-Z — what is actually in this machine

CPU-Z is the first thing to run on an unfamiliar PC, and it is 3.6 MB.

• Version: v2.10 · Size: 3.6 MB · Windows: 11 / 10 / 7 · Licence: freeware · Developer: CPUID (Freeware)

Processor model, stepping, core and thread count, cache, actual live clock speeds, motherboard model and BIOS version, and — the tab most people come for — exactly what memory is installed, in which slots, at what timings. At 4.9★ across 52,000 reviews it is a genuine standard, and it has been for years.

The trade is that it only reports. It will tell you that your RAM is running at a lower speed than it should, and it will not fix it. That is still the most valuable first step there is, because everything else depends on knowing what you have.

Pick this one if: you are buying, upgrading, troubleshooting or verifying a machine — which is to say, always run this first.

2. GPU-Z — the same, for the graphics card

GPU-Z is CPU-Z's counterpart, and it does one job that has become genuinely important.

• Version: v2.59.0 · Size: 9.4 MB · Windows: 11 / 10 / 7 · Licence: freeware · Developer: TechPowerUp (Freeware)

Exact GPU model, memory type and size, clock speeds, BIOS version, and live sensor readings for temperature, load and fan speed. It also has a fake-card detection feature, which matters more than it should: relabelled second-hand cards sold as newer models are a real problem, and GPU-Z is the standard way to check. At 4.9★ across 47,800 reviews it is trusted for exactly that.

The trade is the same as CPU-Z — it reports, it does not change anything. It is also the tool to have open while you play a game to see whether the card is thermally throttling.

Pick this one if: you are buying a used graphics card, or you want to know why a game is running badly.

3. HWMonitor — the temperatures and voltages

HWMonitor is the one that answers "is it overheating?", and it is 3.1 MB.

• Version: v1.54 · Size: 3.1 MB · Windows: 11 / 10 / 7 · Licence: freeware · Developer: CPUID (Freeware)

Live temperatures for every sensor the machine exposes, plus voltages, fan speeds and power draw, with minimum and maximum values tracked so you can run a load and then check what the peak was. At 4.8★ across 31,200 reviews it is the standard companion to CPU-Z, and from the same developer.

The trade is that the reading list is long and unlabelled in places, so it takes a moment to find the sensor you want. It also does not control anything — it is a thermometer, not a fan controller.

Pick this one if: the machine shuts down under load, throttles in games, or has fans that never stop.

Find the disk space

4. TreeSize Free — where the disk actually went

TreeSize Free answers the question Windows is strangely bad at answering.

• Version: v9.1.5 · Size: 12.8 MB · Windows: 11 / 10 · Licence: freeware · Developer: JAM Software (Freeware)

It scans a drive and shows you a folder tree sorted by size, so the 40 GB you cannot account for turns out to be a cache, an old backup, or a game you forgot about. It drills down instantly and it is far faster than clicking through Explorer. At 4.9★ across 28,400 reviews it is one of the highest-rated tools here.

The trade is nothing much: the free version does the core job well, and the paid version adds reporting and scheduling most people will never want. A full drive is the most common cause of a slow Windows machine, which makes this the highest-value 12.8 MB on this page.

Pick this one if: a drive is full and you have no idea what is on it.

Look at the network

5. Wireshark — what is actually on the wire

Wireshark is the serious network tool, and it is the only one here that requires real expertise.

• Version: v4.2.6 · Size: 76.4 MB · Windows: 11 / 10 · Licence: open source · Developer: Wireshark Foundation (Open Source)

It captures every packet on an interface and lets you filter, decode and inspect them — which protocol, which host, what payload, how long the handshake took. When a connection fails and nothing else can tell you why, Wireshark can. At 4.9★ across 38,200 reviews it is the industry standard, and it is free and open source.

The trade is the learning curve, and it is steep. A capture is thousands of packets and the skill is in the filtering. It is also 76.4 MB, the heaviest tool on this page. This is a professional instrument, not a diagnostic you run casually.

Pick this one if: you need to know exactly what a program is sending, and you are willing to learn the filters.

6. AnyDesk — fixing a machine you are not sitting at

AnyDesk is the remote-access tool, and at 5.2 MB it is remarkably small for what it does.

• Version: v8.0.10 · Size: 5.2 MB · Windows: 11 / 10 / 7 · Licence: freeware · Developer: AnyDesk Software GmbH (Freeware)

Connect to another machine and control it as if you were there, with genuinely low latency and file transfer built in. For helping a relative with a PC problem from another city, it is the best tool on this page — 5.2 MB, no configuration, works through most home routers. At 4.8★ across 68,400 reviews it is widely trusted.

The trade is a serious one and it belongs on the page: remote access tools are the single most common vector for tech-support scams. Never give a connection ID to someone who called you. Free use is for personal use; commercial use expects a licence.

Pick this one if: you support someone else's PC remotely, and you are the one initiating the call.

7. Samsung Internet for PC — the browser that syncs with a Galaxy phone

Samsung Internet is on this list for one specific reason, and it is not that it is the best browser.

• Version: 30.0.1.40 · Size: 124 MB · Windows: 10 / 11 64-bit · Licence: freeware · Developer: Samsung Electronics Co., Ltd.

If you use a Galaxy phone, this is the desktop browser that syncs your bookmarks, history and saved passwords with the browser on it, in one Samsung account. That continuity is the whole value proposition. It is Chromium-based, so sites render exactly as they do in Chrome, and it carries Samsung's tracker blocking. At 4.6★ across 190,000 reviews it is decent rather than beloved.

The trade is that outside the Samsung ecosystem there is little reason to choose it over Chrome, Edge or Firefox, and at 124 MB it is the second-heaviest download here. It is a continuity tool, not a better browser.

Pick this one if: you use a Galaxy phone and you want the desktop half of the same browser.

Fix the drivers

8. DDU — the driver removal that actually removes it

Display Driver Uninstaller is the smallest tool on this page and the one most likely to fix a real problem.

• Version: v18.0.8.0 · Size: 1.4 MB · Windows: 11 / 10 / 7 · Licence: freeware · Developer: Wagnardsoft (Freeware)

A normal graphics driver uninstall leaves registry keys, folders and files behind, and those remnants are the usual reason a fresh driver installs badly — stuttering, crashes, black screens after an upgrade. DDU removes all of it, properly, so the new driver installs onto a clean system. At 4.9★ across 48,900 reviews it is a legend in this niche, and it is 1.4 MB.

The trade is procedure. Run it in Safe Mode, and download the new driver before you start, because you will have no proper display driver in between. Do that, and it fixes problems that nothing else on this page will touch.

Pick this one if: you changed graphics cards, or a driver update made things worse.

9. Driver Easy — the automatic updater, with a caveat

Driver Easy is the automated driver tool, and it is here with an honest warning attached.

• Version: 6.1.1.29841 · Size: 34 MB · Windows: 10 / 11 (64-bit) · Licence: freeware · Developer: Easeware Technology Limited

It scans your hardware, finds drivers it thinks are out of date, and installs them, with a backup and restore feature so a bad update can be undone. At 4.7★ across 950,000 reviews it has by far the largest user base on this page, and the restore feature is genuinely the good part.

The trade is the category itself. Windows Update and the manufacturer's own download page handle almost every driver correctly, and an automatic updater's real risk is replacing a working manufacturer driver with a generic one. Free scanning, paid bulk installing. For graphics drivers in particular, go to the GPU maker and use DDU when one needs replacing.

Pick this one if: you have a machine with many unknown devices and you want a starting point — not as a routine maintenance habit.

The nine, side by side

What none of these fix

A diagnostic tool does not repair anything. CPU-Z, GPU-Z, HWMonitor and Wireshark tell you what is true. Acting on it is a separate step, and DDU is the only tool here that actually changes something.

High temperatures are usually dust and paste, not software. HWMonitor will show you a CPU at 95°C. The fix is cleaning the cooler and repasting it, and no download does that.

A driver updater is not maintenance. Updating a driver that works is a way to break it. Update when something is wrong, not on a schedule.

Remote access is the scammer's favourite tool. AnyDesk is legitimate software. The connection ID is the thing to guard: never give it to someone who contacted you first.

The two-minute version

Unfamiliar machine? CPU-Z then GPU-Z — 3.6 MB and 9.4 MB, run both first.

Overheating or throttling? HWMonitor.

Drive mysteriously full? TreeSize Free — the highest-value scan here.

Graphics driver misbehaving? DDU, in Safe Mode, with the new driver already downloaded.

Helping someone else's PC? AnyDesk — and you make the call, not them.

Every app named here resolves to a page in the FileCobra catalogue — the build fails if one does not. Versions, package sizes and system requirements are read from that catalogue rather than written by hand. Where our ingestion worker has fetched a release itself, it records a SHA-256 of the exact file we serve and publishes it on the app’s page. We do not run an antivirus lab: where a VirusTotal report exists we link it, and where none exists we say so rather than imply one.