The short answer
Measure before changing anything: watch CPU and GPU temperatures during a game and note what they actually reach. Then clean the dust, check the case airflow, and cap the frame rate, which reduces heat output more than any cooling upgrade. Thermal paste replacement is worthwhile on machines more than three or four years old.
Modern processors and graphics cards protect themselves by reducing speed as they get hot, which means overheating usually shows up as gradually worsening performance rather than a crash. Recognising that is what lets you fix it before it becomes a shutdown.
Step 1: measure
Install a monitoring tool
HWMonitor, HWiNFO or the graphics driver’s own overlay. You want CPU package temperature and GPU temperature.
Play for twenty minutes and watch
Temperatures rise over the first ten minutes and then stabilise. The stable figure is what matters, not the peak on startup.
Note the numbers
Broadly: CPU in the 70s to mid 80s Celsius under load is normal, high 90s means throttling. GPU up to about 85 is normal, above that is worth addressing.
Check clock speeds too
A processor dropping well below its rated boost while hot is throttling, which is the performance cost you are actually paying.
Note ambient room temperature
A machine that is fine in winter and struggles in summer is marginal rather than faulty, and the fixes are the same.
Step 2: dust and airflow
This is the free fix and usually the largest single improvement on a machine more than a year old.
- Clean the intake filters, which are removable and washable on most cases. A blocked filter starves everything.
- Clean the CPU cooler fins and the graphics card cooler, holding each fan still while blowing air through.
- Check the case airflow direction: front and bottom fans drawing in, rear and top exhausting.
- Aim for slightly more intake than exhaust, which creates positive pressure and pushes dust out through gaps rather than pulling it in.
- Tidy the cables so they are not blocking the path between intake and exhaust.
- Give the case room, not jammed into a desk cubby with no clearance at the back.
A desktop on carpet draws in a vast amount of dust through the bottom intake. Raising it a few centimetres on a stand, or moving it onto the desk, reduces the dust it ingests dramatically and lowers temperatures within weeks rather than immediately.
Step 3: reduce the heat produced
Cooling removes heat; this reduces how much is generated in the first place, and it is more effective than most cooling upgrades.
- Cap the frame rate. The last few frames per second cost a disproportionate amount of power. Capping at 60, 120 or 144 to match your monitor reduces heat and power substantially with no visible loss.
- Enable adaptive sync and cap slightly below the monitor’s maximum, which is the smoothest and coolest configuration.
- Lower one or two settings that are disproportionately expensive, such as ray tracing or ultra shadows.
- Undervolt the graphics card, which on most modern cards reduces temperature and power significantly for little or no performance loss. It is a slider in the tuning software rather than a risky operation.
- Check for a power limit setting and reduce it by 10 to 20 percent, which typically costs a few percent of performance and reduces heat noticeably.
Step 4: thermal paste and contact
The paste between the processor and the cooler dries over three to five years, and on a machine of that age replacement typically drops temperatures by 10 to 20 degrees. Signs are temperatures that spike very quickly under load and fall quickly afterwards.
Also check the cooler is properly mounted. A cooler fitted with uneven pressure, or one that has loosened over years of thermal cycling, produces high temperatures with no other symptom. Removing and refitting it with fresh paste is the fix.
On graphics cards, the same applies, and it is a more involved job because the cooler shroud has to come off and thermal pads on the memory need replacing too.
Step 5: the cooler itself
If the machine is clean, the paste is fresh and it still runs hot, the cooler may simply be inadequate. Stock coolers supplied with processors are designed to meet the specification rather than to keep temperatures comfortable, and a modest aftermarket tower cooler is one of the best value upgrades available.
For a graphics card, the cooler is not usually replaceable, and improving case airflow around it is what you can control.
Check fan curves before assuming a hardware problem. Some manufacturers ship very conservative fan profiles that prioritise quiet over cooling, and the machine runs hot while the fans are barely audible. Setting a more aggressive curve in the BIOS or the graphics software costs nothing but noise.
Laptops specifically
Laptops have far less room to work with, and the same principles apply in miniature:
- Use it on a hard surface, never on a bed or a lap.
- Clean the exhaust vents, and remove the bottom panel for the dust mat between the fan and the heatsink, which compressed air from outside never reaches.
- Cap the frame rate, which matters even more on a laptop.
- Use the manufacturer’s performance modes, which control fan curves and power limits.
- Consider a cooling pad, which reliably prevents blocked intakes and lowers temperatures by a handful of degrees.
- Undervolting is often locked on laptops, and where available it is particularly effective.
What temperature is too hot?
Broadly, a CPU sustaining high 90s Celsius and a GPU above the mid 80s are worth addressing. Modern chips protect themselves by throttling, so the cost is performance rather than damage.
Does capping the frame rate really help?
Substantially. The final few frames per second cost a disproportionate amount of power, which becomes heat. Capping to match your monitor reduces temperatures with no visible difference.
Is undervolting risky?
On modern graphics cards it is a supported slider in the tuning software, and the worst case is an unstable setting that you reverse. It commonly reduces temperature and power for little or no performance loss.
How often should I replace thermal paste?
Every three to five years for a machine used heavily, or when temperatures have crept up noticeably and cleaning has not helped.
Will more case fans fix it?
Only if airflow is the limit. A clean machine with good airflow and a dried-out paste joint will not improve with more fans. Measure first so you know which problem you have.
The order
Measure for twenty minutes and write the numbers down. Clean the filters, the CPU cooler and the graphics card, and check the airflow direction and the fan curves. Cap the frame rate and undervolt the graphics card, which reduce heat at the source. Replace the thermal paste on anything more than three years old. Then consider a better cooler, once you know the others have not solved it.
