There is an array of telltale signs that can indicate whether your CPU is damaged beyond repaid or not. For instance, if your computer starts and turns off abruptly or if your system just randomly turns off at times, then it could indicate that your CPU is bad.
However, the issues that you can potentially get with a bad CPU are similar to those that you would also expect if any other critical component like the motherboard or RAM were damaged.
Hence, it is important to first isolate where the problem lies before concluding anything.
Hence part of knowing how to tell if CPU is bad or dead is to check the rest of your system components as well, particularly the motherboard.
In this article below we talk about this in detail.
Primary Step: Isolate Where the Problem Lies
The first step to take is to pinpoint where the problem lies. Many times you may assume that your CPU is acting up but the actual issue may lie with the motherboard or the RAM.
Test if Motherboard or CPU is Bad
To check if the issue lies with the motherboard or the CPU, remove everything from the motherboard including the CPU and check if it still works.
Read in Depth: How to Test Motherboard Without CPU?
Check the CMOS Battery for Good Measure
Often a dead CMOS battery can cause booting up issues on PCs.
As a first measure of isolating where the problem lies, try replacing the CMOS battery.
Check For POST Indicators
Technically what you are trying to achieve is for the motherboard to perform the POST (Power On Self Test). POST is the very first test a computer performs to check if all the hardware is working.
While the motherboard will obviously NOT pass the POST successfully since you have everything removed, it will at least indicate if the motherboard is operating correctly.
In the POST test without CPU connected, you will NOT see anything displayed on the screen, what you will observe are beep codes and LED flashes – which are codes indicating where the problem lies.
So for instance, the beep codes have meaning.
- 1 Beep – issues with the memory
- 2 Beeps – issues with the motherboard
Your motherboard WILL need to have a beep code speaker however. Most mid to high end motherboards do have this speaker. For budget motherboards, you may need to invest on one separately:
Also Read: Will Motherboard Post Without CPU?
Some motherboards do not have either the beep code or the LED indicators. Here you can check if the motherboard is at least powering on by checking if the CPU fan or the system fans attached are turning on.
Outcome of this Test
There can be two outcomes to this test where you isolate the motherboard from everything else.
Case No. 1: The motherboard does not power on at all
This could indicate an issue either with the motherboard or with the Power Supply Unit. The next step would be to check the Power Supply Unit.
Case No. 2: The motherboard does turn on
This could potentially indicate that the motherboard is good and that if your PC isn’t working it could be due to a bad CPU.
However, it could also be possible that the motherboard CPU Socket is damaged. So in this situation your motherboard will turn on, but any installed CPU still wouldn’t work due to a damaged CPU socket.
You could further isolate the problem by either testing the CPU on another motherboard with the same socket or by mounting another CPU in the current motherboard socket. However, this test is not possible for most users as most do not have a spare motherboard or a CPU lying around.
Also Read: How to Tell if PCIe Slot is Bad?
Secondary Step: Check if the CPU is Being Provided Adequate Cooling
You have to make certain whether your CPU is actually dead or is it just not working stability.
If your PC starts but freezes or shuts down unexpectedly at random times without warning, then it could indicate that your CPU is overheating.
How to Know if Your CPU is Overheating?
For this, I recommend using a simple third party software called CoreTemp.
With this you can monitor the overall temperature of your CPU.
This utility tells you what the recorded minimum and the maximum temperature of the CPU.
It also tells you what the Tj Max of your CPU is is.
Tj Max is a very important number as it indicates the max temperature threshold of the CPU before it starts to throttle and even shut down.
If your Max temperature recorded exceeds the TJ Max then it could indicate an overheating problem
How to Fix Overheating
There are two ways to fix overheating. The first is to provide adequate cooling through airflow. The other is to check if the thermal paste between the CPU Cooler and the CPU is adequate applied.
If you have identified that your CPU is indeed heating up then rest assured that your CPU is not permanently bad or dead.
Signs on How to Tell if CPU is Bad or Dead?
If you have both isolated the problem and also made sure that the issue does not lie with the heating, then the following extra pointers would help indicate if your CPU is bad or dead.
1. Physical Appearance – Burn Damage – Damaged Pins
You can also recognize a bad CPU by having a look at the motherboard. The CPU could potentially appear burned and blackened, probably due to excessive overheating or perhaps a short circuit.
The circuit board surrounding the CPU may also have burned spots. This denotes that the CPU has been damaged permanently. In this situation it is recommended to immediately disconnect the power supply to the board and to cease from turning the system on.
Another very common issue with processor is damaged pins. If one or more of the pins on the processor are either damaged or bent, that can cause your processor to mall function.
Not all CPUs have pins; only Pin Grid Array CPUs have pins on them.
PGA vs LGA
The damage to pins depend upon the type of processor you have i.e Land Grid Array (LGA) or Pin Grid Array (PGA).
LGA processors are utilized by Intel mostly. These do not have pins on the processor but instead have pins on the motherboard. So to check for damaged pins on an LGA based system, you’ll have to check it on the motherboard CPU socket.
PGA is utilized by AMD. These processors have visible pins on them that can be damaged or bent if not taken care off properly.
2. Boot Issues
We covered this point above, but it is an important telltale sign. In most cases, a bad CPU causes a computer not to undergo the boot process upon turning the PC on.
The screen may remain blank though and you may hear hard drive or fans spinning, but the computer may not respond even with a keypress.
3. POST Errors and Beeping Sound with CPU Connected
We discussed this earlier as well, but if you have a CPU connected, the motherboard will still go through a series of system checks or POST.
If all the tests pass, the computer will boot up automatically and the operating system will load normally. In case if the test fails due to a bad CPU, the system will not move past the POST and the motherboard may create beeping sounds.
The number of beeps is a code that further indicates where the problem is detected. For example, the AMI BIOS beeps five or seven times upon detecting a bad CPU.
4. Screen Freezing and System Lagging
If your PC does pass the POST test and loads the operating system, you could still face issues caused by a bad CPU.
This includes screen freezing, system lags, and also the infamous Blue Screen of Death (BSOD).
Do note that these issues could also be caused by a damaged RAM stick or GPU. So you may need to perform further isolation.
But as far as the CPU is concerned, I would recommend here that you keep an eye out on the CPU temperature.
Also Read: How to Tell if a PCIe Slot is Bad?
5. Did You Recently Overclock Your CPU?
If a problem with your system and your CPU started AFTER you fiddled around with overclocking it, then the overclocking could have caused damage to it.
A CPU can permanently get damaged if overclocked incorrectly and excessively beyond safe parameters and particularly if adequate cooling is not provided.
Dead CPUs caused by overclocking are NOT covered by warranty.
Also Read: How to Check if CPU is Overclocked
We looked at different ways on how to tell if CPU is bad. While it is unlikely that a CPU can fail so easily, it is still worth troubleshooting where the problem lies if your PC is acting up.
The integral part of testing if your CPU is bad or dead is to start off by isolating where the problem lies. You could also start off by physically inspecting the CPU. Burn damages or bent pins are a telltale sign of a damaged CPU.
However, if everything looks good physically you should start by isolating it from the motherboard and checking if the motherboard is operating fine.
If motherboard is good, but if your system is acting up in the boot process or when the OS is loaded and your system freezes or shuts down abruptly that could indicated CPU issues. Start by checking the CPU temperature here.
Also, if your CPU is malfunctioning entirely then the POST test at the system startup could be your friend. The POST test creates beep code if it detects problems with the hardware which is a great way to tell where the problem exactly lies.
Also Read: What Happens When CMOS Battery Dies?