How To Tell If Processor Is Bad Or The Motherboard

Has your PC been giving you a hard time lately? Or worse yet, is it simply refusing to turn on anymore? The issue may lie in your processor or motherboard, and there’s a way to tell which is the problem. 

It’s not hard to rule out which of these components is broken. I’ll review several ways to do so, starting with the easiest.

1. Ensure Your PC’s Components Are All Connected Properly

Before doing anything else, you should ensure all the cables and components in your PC are firmly connected. I know. That sounds like a chore. But we must get this step out before checking for more serious errors. 

Computers are complex machines. It’s a miracle they run as well as they do. They’re made up of several components, and all it takes for a computer to stop functioning correctly is for one of these many components to lose connection or fail. 

Here’s what you should check:

  • Your PC’s power cable. It should be firmly connected to both port and socket. 
  • Your PC’s PSU (Power Supply Unit). It should be connected and supply power to the motherboard. 
  • Your PC’s storage devices (HDD/SSD). They should be attached to and receive power from the PSU. 
  • Your RAM sticks. They should be secured firmly in their slot. You’ll hear a click when they’re pushed in correctly. A computer won’t boot if the RAM isn’t in place. 
  • Your case, fans, and internal fans. They should be drawing power from the PSU and fully operational. Overheating can cause a system to shut down. We’ll talk more about this shortly. 
  • Your GPU. If it has a power consumption of over 75 watts, it should be connected directly to the PSU with a 6/8-pin connector. 
  • Expansion cards. Check all expansion cards are plugged all the way into the motherboard slots and that they are straight and not at an angle in the slot.

If adjusting any of the above fixed whatever problem you were experiencing, the issue likely didn’t lie in your CPU or motherboard. If you’re still facing a problem, let’s move forward. 

2. If Your PC Can Turn On, Test the CPU

A Prime95 stress test is running on a computer.

With motherboards, serious problems usually result in the PC not turning on at all. 

If your PC is capable of turning on but isn’t functioning normally (lag spikes, crashes, freezes, generally poor performance), you will likely have a CPU problem

In that case, you should conduct a stress test. As the name implies, a stress test reveals how well a CPU performs under maximum load. Now, CPUs usually don’t hit maximum load in daily use, but the stress test is still a handy tool to determine the nature of the problem.

If your CPU cannot tolerate the test and crashes, you’ll have a good lead to pursue. To conduct a stress test, you’ll need to download third-party software. I recommend using CPU-Z.

It lacks the fancy features you may find in some other CPU testing software, but it makes up for it in simplicity and effectiveness. You’ll also need temperature-monitoring software to monitor your CPU’s core temperatures in real time while it goes through the stress test. 

Your graphics driver software may be able to show you CPU temperatures without you having to download an additional application. AMD’s Radeon Software, for example, shows you your system’s internal temperatures in Performance>Metrics. 

If you don’t have built-in temperature monitoring, I recommend downloading MSI Afterburner. It shows you CPU temps and some other metrics. 

Now, back to the stress test:

  1. Launch CPU-Z.
  2. Wait for it to load. 
  3. Navigate to the second to last menu: Bench.
  4. Select Stress CPU.
  5. Monitor your CPU’s temperatures. 
  6. Keep the stress test going until temperatures stop climbing. This usually takes under a minute, but don’t be worried if it takes somewhat longer. 
  7. Stop once temperatures peak. 

Now, if you were to use a faulty CPU during this process, your PC would likely shut down. Stress tests push CPUs to their absolute limit.

A faulty CPU won’t be able to tolerate the stress for long and will either freeze up, crash, or initiate a shutdown

Fix Your CPU Temperatures

CoreTemp Software is running, showing the CPU temperature.

If your PC passes the stress test without crashing, your CPU will likely be okay. The poor performance is likely not caused by your CPU or motherboard. It may be your RAM, storage, or GPU.

If it did crash, though, you might have an overheating problem. It’s the more likely scenario compared to your CPU malfunctioning. CPUs have incredible durability—they can easily go a decade without suffering from noticeable degradation in performance. 

You can tell if overheating was the culprit by analyzing how hot your CPU got before shutting down. Most CPUs will throttle once they hit 184 °F (90 °C) and shut down completely to prevent damage once they break 212 °F (100 °C).

So, if your monitoring software showed you figures somewhere in that ballpark, you likely have an overheating problem. 

The good news is that you can easily manage an overheating CPU with a few easy steps. 

Doing the above will help lower your CPU temperatures significantly. You’d be surprised at how much of a difference these small adjustments can make.

Test the CPU Again

Once you’re done improving your PC’s capacity for cooling, run the stress test again. Your temperatures should be much better this time, low enough to prevent your CPU from throttling or shutting down. 

If that fixed things for you, congrats. 

However, the chip is likely faulty if your PC crashes again despite the CPU being below throttling temperature (<184 °F or <90°C ). It will have to be checked by a professional. 

3. If Your PC Isn’t Turning On, Test the Motherboard

What if your PC isn’t turning on at all? How do you diagnose the issue, then? In this case, the problem will most likely lie within the motherboard or the power supply. Even a roughed-up CPU will show signs of life and get you to the BIOS screen

On the other hand, a damaged motherboard will refuse to turn on and alert you of a problem with beeps and boops. 

Check That Your Motherboard Is Receiving Power

A motherboard's LED are on indicating power.

If your PC refuses to turn on, the first step is to check whether or not the motherboard is receiving power. The easiest way to do this is to look for the LED lights that glow when it receives power.

No glowing lights mean no power. In some cases, however, you can still have motherboard lights that stay on even after shutdown.

Fans are another solid indicator. Fans connected to your motherboard won’t spin without power. If your motherboard powers your CPU cooler, it won’t spin either. The important thing to note here is that most of what appear to be motherboard problems are power supply problems in disguise.

Like CPUs, motherboards are resilient hardware and won’t give out unexpectedly. They can last up to 20 years under optimal conditions. 

Check the cables connecting it to the power supply unit if your motherboard isn’t receiving power. Check the PSU itself, too. Is it active? Is the PSU fan blowing?

If the PSU is in perfect health but still unresponsive, you can confidently conclude that the fault lies in the motherboard. 

Motherboard Receiving Power, But PC Still Not Booting?

If your motherboard receives power (LED lights glow and fans spin when you press the power button) but the system fails to boot up, your RAM sticks or storage device may be at fault. If this is the case, you’ll hear your motherboard beep. It may beep once, twice, or keep going.

The number of beeps does carry a meaning, but it’s impossible to interpret without knowing your motherboard’s BIOS manufacturer. Here’s a more detailed guide. Essentially, the number of beeps produced corresponds to the computer component producing an error. 

Again, the RAM sticks or storage devices are usually at fault. Some motherboards will tell you if your CPU is overheating/faulty by beeping. Very rarely will the motherboard be faulty, but there’s also a beep code. 

If your motherboard beeps, listen closely and try to make out what it’s trying to tell you using the above resource. Given the absurd number of possible faults that can cause a PC not to boot, motherboard beeps are a godsend.

Signs That Your Motherboard Is Faulty

Even though it’s less likely for a motherboard to go bad, here are the signs. 

  • A burning smell. Only the motherboard or the PSU produces a burning smell upon damage. If you notice this, disconnect your PC from the wall socket immediately. 
  • Decoloration of the motherboard. This indicates severe heat stress. 
  • Blown capacitors. This indicates obvious physical damage. 
  • No beeps. If your computer doesn’t boot up at all and you’re certain that the board is receiving power from a healthy PSU, then no beeps are a bad sign.

Unfortunately, you cannot do much to fix a faulty motherboard. Once it’s gone, it’s gone for good. You can get it serviced by a professional but don’t expect the odds to be in your favor. 

Before you send your motherboard off to be serviced, ensure you’ve eliminated other potential causes for your boot error, such as an unhealthy PSU, faulty or loosely connected RAM, or a faulty storage device

4. Use a Second Processor

A woman is holding a spare CPU above a motherboard before installing it.

If you haven’t been able to figure out the problem using the above techniques, you may have to reverse-engineer the source of the problem. To eliminate the possibility of it being a CPU problem, use a different processor. Run a stress test on the new processor to see how it performs. 

You’ll have your answer if the new processor solves your PC’s problems. Whether or not a faulty processor can be repaired depends on the nature of its fault. Overheating, for example, can easily be dealt with at home.

Bent or otherwise deformed processor pins, on the other hand, are best treated by a professional or an expert. CPU chips are delicate, and I don’t advise handling one unless you know what you’re doing.

If the new CPU doesn’t fix or improve the condition of your PC’s problems, your original CPU is likely fine. Either that or the CPU socket on your motherboard has gone bad, in which case it will alert you with beeps. 

5. Use a Different Motherboard

A desktop computer's motherboard.

You can use a different one to rule out (or confirm) an error with your motherboard. Admittedly, that’s a pretty inconvenient and arduous process. 

You would have to separate your computer components from your current motherboard and reattach them to the new one. This will take an entire disassembling and reassembling of your PC.

Honestly, a far better option is to rule out errors with the other components using replacements. 

It would be far more practical to:

  • Test a different power supply. 
  • Test different RAM sticks. 
  • Test a different storage device. 
  • Test a different GPU. 

You should have already tested your CPU by now. Doing so again won’t be necessary. 

Now, these are several components instead of just one motherboard. But they’re all portable, and you can attach and detach them pretty easily one by one. 

You won’t be able to do this testing unless you have an extra PC at home. If you’re at this point without having arrived at an accurate diagnosis of your problem, much less a solution, it’s best to seek professional help.