220-1101 Question 300
Single answerThermal paste/padsA technician replaces a desktop CPU and installs the heatsink that came with it. The system powers on, but after 5 to 10 minutes under load it shuts down unexpectedly. In the UEFI hardware monitor, the CPU temperature rises rapidly. The technician removes the heatsink and notices the pre-applied thermal compound was smudged during the first installation attempt. What should the technician do NEXT to correct the problem?
- A
Clean both the CPU heat spreader and heatsink base, apply a small amount of new thermal paste, and reinstall the heatsink evenly
- B
Add more thermal paste on top of the smudged compound and tighten the heatsink as much as possible
- C
Replace the thermal paste with a thermal pad placed over the top of the installed heatsink
- D
Leave the existing compound in place and increase the CPU fan speed in BIOS to compensate
Show answer and explanation
Correct answer: A
Explanation
This question tests practical troubleshooting of overheating after CPU installation. Thermal paste is intended to fill microscopic gaps between the CPU heat spreader and the heatsink base, improving heat transfer. If pre-applied compound is smeared, lifted, or contaminated during installation, technicians should clean it off and apply fresh compound before reinstalling the cooler. This aligns with standard PC hardware best practices and common CPU cooler manufacturer guidance: use a clean contact surface, apply only the recommended amount of thermal compound, and mount the heatsink evenly to ensure proper pressure and coverage. Using too much paste, stacking new paste on old paste, substituting an inappropriate pad, or relying only on fan speed are common mistakes that can lead to continued overheating and thermal shutdowns.
- A. Correct.
Correct. If pre-applied thermal compound has been disturbed or contaminated, best practice is to remove the heatsink, clean off the old compound from both contact surfaces with an appropriate cleaner such as isopropyl alcohol, apply fresh thermal paste in the proper amount, and reinstall the heatsink with even pressure. This restores proper thermal transfer between the CPU and heatsink.
- B. Incorrect.
Incorrect. Applying additional paste over smudged or contaminated compound can create uneven coverage, trapped air, and poorer heat transfer. Overtightening is also not the fix and can risk damaging mounting hardware or the motherboard. The issue is the compromised interface material, not simply a lack of pressure.
- C. Incorrect.
Incorrect. A thermal pad is used between heat-generating components and a cooling surface where designed by the manufacturer, not placed on top of an already installed heatsink. It would not improve the thermal interface between the CPU and heatsink base. Replacing paste with a pad is only appropriate if the cooling solution is specifically designed for one.
- D. Incorrect.
Incorrect. Increasing fan speed may reduce temperatures slightly, but it does not correct poor contact or a damaged thermal interface. If the compound was disturbed, the core problem is inefficient heat transfer from the CPU to the heatsink. Cooling the heatsink more aggressively will not fully compensate for that.