Why Is My CPU Overheating? (4 Causes & How to Fix High Temps)

Is your PC roaring like a jet engine, dropping frame rates mid-game, or thermal throttling down to a crawl? Your processor might be overheating.

Your CPU (Central Processing Unit) is the heart of your computer. When it runs too hot, your system aggressively cuts its clock speed to prevent permanent hardware damage—leading to game stutters, sudden blue screens, and full system shutdowns. Here is how to diagnose why your CPU is overheating and how to bring your temperatures back down to safe levels.

Quick Reference: Is Your CPU Running Too Hot?

Before diving into troubleshooting, check your processor temperatures under load using free monitoring software like HWMonitor or Core Temp:

4 Main Reasons Your CPU Is Overheating (And How to Fix It)

1. Dried Out or Improperly Applied Thermal Paste

Our photo above is a GPU die, but the principle is the same, very dry thermal paste leading to overheating!

Thermal paste acts as a heat conductor, filling microscopic imperfections between your CPU's integrated heat spreader (IHS) and the metal cold plate of your cooler. Over 2 to 4 years, factory thermal paste dries out, cracks, and loses its ability to transfer heat effectively.

• The Symptom: Your CPU temperatures instantly spike to 90°C or higher the moment you launch a game, even if your fans spin up to maximum speed.
• The Fix: Clean off the old thermal compound using 90%+ isopropyl alcohol and a lint-free microfibre cloth. Apply a pea-sized drop of fresh, high-performance thermal paste to the center of the processor, then re-mount your cooler with even pressure. You can grab a tube of high-performance Thermalright TF7 thermal paste here.
• The Common Builder Mistake: If you recently assembled or upgraded your system, ensure you removed the protective clear plastic film from the bottom of the CPU cooler heatsink. Leaving this sticker on is one of the most common causes of instant thermal throttling on new builds.

2. Dust Buildup & Blocked Airflow

Computer cases pull in ambient air, acting like dust magnets over time. Dust buildup forms an insulating blanket over metal heatsink fins, choking off airflow and trapping heat inside your PC case.

• The Symptom: Temperatures creep up gradually over a 15-to-30-minute gaming session as heat builds up inside the chassis.
• The Fix: Shut down and unplug your PC. Use a can of compressed air to thoroughly blow out fan blades, radiator fins, and mesh dust filters. Hold fan blades still while blowing air to protect their bearings from over-spinning. Ensure case fans are arranged in a proper push-pull configuration (front/bottom intake, rear/top exhaust).

3. Pump Failure or Air Bubbles in an AIO Liquid Cooler

All-In-One (AIO) liquid coolers provide excellent thermal management for multi-core processors, but they contain mechanical pumps and coolant loops that can fail over time.

• The Symptom: One liquid tube feels burning hot while the other feels cold, or you hear a rattling/gurgling sound coming from the CPU block. You may also notice your processor idling at 60°C to 70°C+ immediately upon booting.
• The Fix: Check your motherboard BIOS or control software (such as iCUE or NZXT CAM) to confirm the pump RPM reading (typically 2,000 to 3,000 RPM). If RPM reads 0, verify that the SATA power connector and pump headers are securely connected. If the pump is silent and non-functional despite receiving power, the internal motor has failed and requires replacement.

4. Insufficient CPU Cooler for Your Processor's Power Output

Modern multi-core processors draw significant power under heavy gaming and rendering workloads. Basic stock coolers or entry-level air towers simply lack the surface area to dissipate heat from high-TDP (Thermal Design Power) modern processors.

• The Symptom: Desktop idle temperatures look fine (35°C–45°C), but spike to 95°C+ during CPU-heavy gaming or rendering tasks.
• The Fix: Upgrade to a dual-tower air cooler or a 240mm/360mm AIO liquid cooler designed for your processor class. If you are planning a full hardware refresh, use our Custom PC Builder Tool to match your thermal requirements with compatible coolers and hardware.

Final Thoughts: Maintenance vs. Hardware Upgrades

Most CPU temperature issues can be resolved with basic maintenance—cleaning dust filters, applying fresh thermal paste, or adjusting fan curves in your BIOS. However, if your liquid cooler pump has failed or your old cooler can no longer manage modern game loads, running your chip at peak thermal limits will shorten its operational lifespan.