Preventing Overheating

If you want to ensure that you won’t face overheating, random crashes (resets and the infamous “Blue Screen of Death”) and performance issues with your PC you should check whether it is assembled 100% correctly or not. In this tutorial we will show you where to look for assembling errors on your PC.

First, let’s start with the PC assembly itself. The errors describe on this page can overheat your PC thus causing random problems like random resets and crashes (PC “freezing”, “Blue Screen of Death”, etc).

  • Antistatic foam: Most motherboards come from factory with an antistatic foam (usually pink, white or black) in their packing. Many technicians, when installing the motherboard to  the case, pinch this foam between motherboard and metallic chassis, thinking that this procedure will avoid that motherboard from touching the case metallic frame. It happens that this foam holds motherboard-generated heat, hindering the normal airflow that exists between motherboard and the case chassis. Therefore, it is quite common that a computer assembled using this foam crashes or issues random errors, due to the overheating.

Antistatic foamFigure 1: Pink antistatic foam that comes with the motherboard.

Antistatic foamFigure 2: The use of antistatic foam below the motherboard prevents the correct airflow and causes overheating. Don’t put this foam inside your PC!

  • Internal main power cord: In AT cases it is quite common to have the main power cord that connects the power supply to the power-on switch in front panel hanging loose over motherboard, often hindering the heat dissipation and even contacting the processor fan, causing it to stop running and PC to crash due to overheating. The ideal would be to lay this cable to the power supply switch by the right side of the case (facing front of case in upright position), in the upper part of the frame, and not hanging loose by left side, as it is common to find. Since AT cases are used only on very old PCs, you probably won’t face this issue, however we kept it listed here for historic purposes.

Case Power CableFigure 3: Correct place to lay the power cord cable on AT cases.

  • Other loose cables: The same idea applies to all other cables inside the PC, like the power supply cables and the flat cables used to connect the hard disk drives, optical drives and floppy disk drives. You should fasten these cables with a cable holder and put them inside an empty 5 ¼” bay in order to prevent these cables from blocking the airflow inside the PC and also preventing them to stuck the CPU fan.

Cable holderFigure 4: Cable holders are the perfect tool for organizing cables inside your PC, preventing overheating.

  • Thermal grease: If you are facing overheating problems with your CPU, you should check whether thermal grease was correctly applied on the CPU or not. We wrote a full tutorial on this subject, so you should read it.

  • Under dimensioned case: Cases look all the same, but they aren’t. Current Intel CPUs (Pentium 4 “Prescott” and beyond) require cases with a side duct in order to improve the airflow inside the case. If you don’t use a case with this side duct you may face overheating problems. We wrote a full tutorial on this subject, which you should read.

  • Extra fans wrongly installed: If your case has extra fans, you should check if they are installed on the right position, i.e., blowing the air in the right direction. Fans installed on the rear part of the case must be installed pulling the hot air from inside the PC case to the outside. Fans installed on the front part of the case must be installed pushing cold air from outside the case to the inside. Putting your hand near the fan should be enough for you to feel which way it is blowing air. If any extra fan is reversed, just remove it from your case and install it again, flipping it over. In Figure 5, you can see how extra fans must be installed.

Extra fansFigure 5: How extra fans must be installed.


Gabriel Torres is a Brazilian best-selling ICT expert, with 24 books published. He started his online career in 1996, when he launched Clube do Hardware, which is one of the oldest and largest websites about technology in Brazil. He created Hardware Secrets in 1999 to expand his knowledge outside his home country.