Whether you want to make sure that your computer's hardware is properly functioning, benchmark it, or just want to inspect a second-hand computer you're thinking of buying; the benchmarking tools and stress testing utilities in this list will help you a lot.
You can use these apps and software to thoroughly check up on a used laptop or desktop pc, as they enable you to spot any faulty hardware component or find out how much performance being impacted by its usage. So, this guide should also serve as a life-saver for someone who's looking into a second-hand deal.
All-in-One, multiple tests and feature-packed software:
[Commercial] Made by UL Benchmark, PCMark 8 is a very robust suite of utilities built in one apps, it tests about everything, even the battery life and some well-known applications load times!
[Commercial] Also made by UL Benchmark, 3DMarks has got multiple simulations that will mainly stress test the CPU and GPU for various APIs (like DirectX9, 11 and Directx12, )
[Commercial] Geekbench measures your processor's single-core and multi-core power, for everything from checking your email to taking a picture to playing music, or all of it at once. Tests your GPU's power with support for the OpenCL, CUDA, Vulkan and Metal APIs; to test system's potential for gaming, image processing, or video editing
[Commercial - Free Trial Available]
PassMark, another giant benchmarks database owner, offers several tools for testing pc hardware to check its stability, like 
PassMark PerformanceTest. BurnInTest is pretty similar to PerformanceTest but claimed to be more intended for more professional level.
AIDA64 offers a complete set of tools to benchmark, overclock, monitor, fine-tune, and troubleshoot Windows based desktop and mobile computers.
[Free] Cinebench is a real-world test suite that evaluates your computer's performance capabilities. It's the perfect tool to compare CPU and graphics performance. And best of all: It's completely free.
[Free] UserBenchMark is well-known for its huge database of gpu and cpu scoring. Their software is kinda basic compared to the ones above, softly testing the processor, graphics, fixed drives, memory and usb.
These applications are specifically designed to stress test the central processing unit:
[Free] It is commonly used as a stability test for overclocked computers. Prime95 includes a "Torture Test" mode designed specifically for testing for errors, ensuring the correct operation of the program.
[Free] Bring your PC to its limits with the freeware stress test tool HeavyLoad. HeavyLoad puts your computer under a heavy load and lets you test whether it will still run reliably.
These applications will specifically test the graphical processing unit:
[Free] Extreme performance and stability test for PC hardware: video card, power supply, cooling system. Check your rig in stock and overclocking modes with real-life load! Also includes interactive experience in a beautiful, detailed environment. Using the newest workloads is recommended, so running the "Superposition" or "Valley" simulations should do the trick.
[Free] FurMark is a very intensive OpenGL benchmark that uses fur rendering algorithms to measure the performance of the graphics card.
A faulty RAM is pretty common hidden problem in used computers, so here is a list of software to check the Random Access Memory:
[Free] A thorough, near perfect, but could take too long sometimes, that will run from UEFI with very practical testing algorithms.
[Free] Lightweight, standalone utility that lets you check your system memory for problems at the hardware-level. It has a graphical interface, and can be run from within Windows.
For storage units tests:
[Commercial - A free trial available] Monitoring hard disk's health with very advanced features.
[Free - With some limited paid features] A reputable alternative to Hard Disk Sentinel, might not be as professional, but cheaper and it's definitely worth a try for its sufficient amount of features which get the job done.
[Free] The most basic tool here, but it can also reveal lots of useful information about the disk like (write and read speed).
Tools to monitor every detail of internal hardware's status and other useful numbers
[Free] HWiNFO is a great utility to retrieve the tiniest information about all parts inside your computer. It's as robust as the commercial software Aida64 in terms of the amount of diagnostic info about the computer hardware. One great feature that is really useful when testing a second-hand laptop is the ability to read the battery's built-in wear sensor which serves as a good indicator to how much lifespan is left for that battery.
Find out if your screen has got any dead pixels.
[Free]
InjuredPixels fills the entire screen with a primary or custom color, helping you to easily spot pixels that do not match the selected color.
Or you can try web app alternative called: 
Monteon.
My personal favorites in this list (which I always keep on my portable USB stick for troubleshooting a suspected hardware and when buying a used computer or even for buying a single component) are:
Whether you want to make sure that your computer's hardware is properly functioning, benchmark it, or just want to inspect a second-hand computer you're thinking of buying; the benchmarking tools and stress testing utilities in this list will help you a lot.
You can use these apps and software to thoroughly check up on a used laptop or desktop pc, as they enable you to spot any faulty hardware component or find out how much performance being impacted by its usage. So, this guide should also serve as a life-saver for someone who's looking into a second-hand deal.
#MZ_YI Edited by: Malaz YI.
Comments
Really useful list. It would be great to expand it to a couple of tools for mobile devices eventually. Thanks for sharing!
Thank you Mauricio, I'm really glad you liked it! I was actually thinking of making separate list for mobile devices tools, I will try to make one as soon as I get enough time to do so. Thank you again mate, your kind comment is highly appreciated...Take care and have a nice one!