How To Check If CPU Is Working (Full Processor Test Guide)

You’re in the right place if you need to check a CPU to ensure it works properly. Whatever your reason is for evaluating the working condition of a computer processor, we will provide you with the necessary steps to know if you have a functional component or a paperweight.

To determine if a CPU is working correctly, look for any bent pins, damaged pads, discoloration, warping or bending, or marked or scratched surfaces. Then, perform software tests to test if the CPU works and remains stable over time and under heavy workloads.

Now we will go through the details in this how-to guide for accomplishing all these checks and finally determine the state of the CPU you wish to examine.

We will start with the visual inspections and proceed with the software tests to complete the testing.

A rendering of a typical CPU for a desktop computer.

Physical CPU examination

Important: When handling any CPU, it’s always best to wear a pair of clean antistatic gloves and never touch the pins or pads of the CPU, or the processor socket.

Obviously, we don’t want to see any physical markings or damage to the CPU, but here are some finer points to inspect.

Feel free to use a magnifying glass or anything to provide magnification or a more precise inspection of the CPU.

Bent or broken-off pins

A CPU with bent and broken pins is highlighted with a red circle.

This is pretty obvious, but I felt I needed to mention it. Sometimes pins can be so slightly bent that it’s difficult to spot without careful inspection.

Look alongside the sides or edges of the CPU to bring the rows of pins into view. This helps you to identify any pins slightly out of place.

Broken pins will be more obvious but can easily be overlooked if you aren’t looking out for them.

I have written a short segment on how to fix broken pins. However, it isn’t recommended if you have the option to avoid the processor entirely instead.

If it were me, I would avoid such a CPU as proper care wasn’t taken to handle it. It makes me wonder what else is perhaps damaged that I cannot see.

Damaged or bad CPU pads

A CPU with a damaged contact pad.

The pads under the Intel processors are delicate and should never be touched with a bare finger.

Once your skin’s oils settle on the pads, discoloration or tarnished effect and poor contact will form over time.

Look at the pads using a magnifying device to compare the individual pads to ensure no damage anywhere.

If you can see traces of physical damage, it usually means that the CPU was mishandled at some point and may cause connectivity issues with the pins on the motherboard CPU socket, depending on how bad the damage is.

This kind of damage can produce intermittent faults or startup failure. So be meticulous when inspecting the pads so you can spot potential problems that may be causing improper behavior of the CPU.

If some thermal paste has been accidentally messed on the contact pads, remove it using thermal compound remover.

Rubbing alcohol will be ineffective in removing all the thermal paste deposits effectively.

Keep repeating the cleaning process with sections of lint-free cloth and thermal removal fluid until everything is properly clean.

Always wear gloves when doing this, so you don’t touch the copper contacts in the process.

Finally, use a thermal surface purifier to make sure all unwanted residue has been removed.

If you notice that the pads look tarnished from someone mishandling the processor, employ the eraser cleaning method.

Ensure all the eraser filings have been completely removed before installing the CPU into the motherboard socket for testing. This is the most crucial step!

After this cleaning method, you will see the copper pad color will be improved and will make far better contact with the contact pins from the socket.

Discolored areas

Check all around the CPU. Top to bottom. If you notice any discoloration of any kind, avoid using this CPU.

Sometimes you can notice darker regions on the top of the CPU. A blue tint in the metal can also indicate previous overheating issues.

Check the pads or pins for the same thing. The PCB area should be discolored, and is a big red flag if any area is inconsistent with its proper color.

Warping or bending

Look carefully at the PCB area of the CPU and make sure that everything looks properly straight and nothing is curved or bent.

Sometimes CPUs are installed the wrong way, and the ILM (Independent Loading Mechanism) gets forced to lock the processor in place, causing damage to it.

Another way warping or bending can occur is by over-tightening CPU coolers to the motherboard.

The motherboard usually takes the biggest knock from this, but in extreme cases, the processor can be warped, especially in conditions where lots of heating up and cooling down occur.

Uneven or damaged IHS

A CPU with IHS removed, otherwise known as delidding.
A CPU with IHS removed (delidded)

The CPU IHS (Integrated Heat Spreader) or lid is the metal piece that makes contact with the CPU cooler’s heatsink.

Apart from providing some extra protection, it also acts as a heatsink to transfer the heat from the processor to the CPU cooler.

Check the surface of the processor lid for scratches, scuff marks, or oddly worn patches that isn’t even across the surface.

Scratches may mean someone used a tool to scrape off the old thermal paste. In this case, I would be extremely cautious in trusting the CPU’s condition.

Uneven wear or scuff marks could mean that the CPU heatsink used with the processor wasn’t making true contact along the surface and applied more pressure on a particular lid area and not over the whole surface.

This could imply that the CPU suffered from improper cooling and may have overheated at some stage, causing internal damage.

Check around the lid to see if there are any signs of attempted delidding. For example, you will see fine scratches or sometimes a punctured spot where someone may have used a tool to remove the CPU lid.

Requirements for testing

To properly test a CPU, you will need the following:

  • A proven working and stable motherboard.
  • Proven stable RAM.
  • A fully working operating system drive.
  • A freshly installed operating system.
  • Absolutely no overclocking has been applied.
  • Good quality, fresh, and properly applied thermal paste.
  • A good quality CPU cooler.

If these requirements are met, you can safely proceed with the tests confidently.

PC system startup

This test will automatically be completed when you install a fresh copy of an OS of your choice.

You will check if the CPU completes the following:

  • First, the processor is in proper functioning order for the computer system to post.
  • Next, the installation media can complete the OS installation process.
  • Finally, the system boots reliably into the newly installed OS.

If the computer hangs or fails to complete the necessary tasks to accomplish this step at any time, you will need to find out if it is the CPU.

You can move on to the next testing phase if you have met the test requirements and you have established that the problems causing the failures aren’t the CPUs fault.

Load test

A Prime95 test in action to stress test a CPU.

Download and install a stress test program of your choice. Here are some recommendations based on which OS you are running:

After installing and running these tests, monitor the results and watch the computer system’s stability during the tests.

If the computer experiences regular freezing, micro stuttering, or restarts, it could mean that the CPU is overheating or isn’t reliable enough to consider in normal functioning conditions.

Double-checking that no overclocking is applied in the BIOS might be a good idea. Check that the base clock speeds are defaulted along with any other multipliers or voltage settings.

In addition to this, ensure that you have installed the cooler properly with good thermal paste. You can read my other article about how to know if the CPU is mounted properly if you need more information.

Otherwise, if the CPU has made it this far, things are looking pretty good, and it will most likely be fine.

But we want to dig into some more testing to ensure that the CPU is working properly under more prolonged use case situations.

Temperature check (Prevent CPU failure)

CPU Temperature is being monitored by Core Temp software.

Now it is time to add in an extra step. Install a temperature monitoring software program to monitor processor temperatures while the load test software goes to work.

Here are some recommendations for temperature testing software on some different computer operating systems:

If the temperature holds below the manufacturer’s recommended maximum temperature, you can move on to the power consumption test.

Otherwise, if the processor runs too hot, you may want to check that the cooler is installed correctly, that you have installed good quality fresh thermal paste, and that enough was applied.

This goes a long way to prevent CPU failure for a computer.

Monitor the Thermal Design Power (TDP)

Now that you have proper load test software in place, you need to watch out that the CPU isn’t drawing more power above and beyond real-world tolerances based on the manufacturer’s specifications.

To do this, use software like Prime95, as mentioned earlier, to indicate how much power the processor is using under load.

Go to the specifications page of your CPU on the manufacturer’s website to look at the suggested TDP.

Other programs include Quick CPU or HWiNFO.

If something doesn’t look right, ensure that no overclocking or voltage tweaks are present in the BIOS and the processor is running at the correct temperatures.

If these conditions are met, I’d be questioning the internal integrity of the CPU, and it may not be operating at its proper efficiency.

In this case, I wouldn’t rely on the CPU as a long-term daily-use component. It would indicate that some risk would be involved in trusting it fully.

Look out for random freezing or micro stuttering

Part of testing a computer processor doesn’t mean that you solely rely on the actual test results from testing software.

Observe the operation of the computer in terms of stability while you set up or use the system to conduct the tests.

Pay close attention to slowdowns, when the mouse pointer sticks, or if programs or games drop frame rates unexpectedly.

Because of the unreliability of so many games in recent years, I recommend that you test various games to avoid blaming the CPU for malfunctions when game bugs can cause issues.

48 Hour or extended soak test

Run the load test software with minimal load settings and make it work for a longer period. You can do this for periods exceeding 48 hours to ensure nothing crashes, freezes, blue screens, black screens, or experiences any screen death.

Games like Dying Light 2, Halo Infinite, and Forza Horizon 5 are good starting points.

Look for free titles in the Steam store or Epic games to get some soak testing done on a tight budget.


And that is a list of my top checks to test that a CPU is working reliably. I hope it has been thorough enough for you to determine the processor in question properly.

I also want to mention that you should never rush the process and take your time when evaluating the condition of a processor.

A lot of times, things tend to surface after spending some time watching closely and don’t always reveal issues with standardized tests.

I wish you the best of luck figuring out if the CPU you are looking at is tip-top or a flop.

At the very least, you could take the computer’s processor to a computer repair shop for them to establish if it works reliably or not.