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Quick answer: Clean both the CPU heat spreader and the cooler base with 90%+ isopropyl alcohol and a lint-free wipe until mirror clean. Apply a pea-sized dot in the center of the CPU, lower the cooler straight down, and tighten the mounting screws in a cross pattern, a few turns each until snug. The pressure spreads the paste into the thin even layer you want.
Step 1 – Remove the old paste
Unclip or unscrew the cooler after warming the paste (run the PC a few minutes first, warm paste releases without yanking the CPU out of the socket). Twist gently to break the seal. Wipe both surfaces with isopropyl alcohol on a coffee filter or microfiber until nothing grey remains, then let them flash dry.
Our pick for this guide: ARCTIC MX-6 Thermal Paste
The pea-dot method here spreads properly only with a paste of the right viscosity – MX-6 is non-conductive and non-curing, so a slightly generous dot cannot short anything or cement the cooler down.
Step 2 – Apply the right amount
Center a 4mm dot on the heat spreader. Variations exist (line for long dies, X for very large chips) and measured differences between them are within a degree or two: coverage and mounting pressure decide the result, not the artistic pattern. Do not pre-spread with a card, it introduces air pockets and mess for no measurable gain.
Step 3 – Mount the cooler properly
- Peel any protective film off the cooler base (the single most common mistake in first builds).
- Lower the cooler straight down onto the dot, no sliding around.
- Tighten screws in a cross pattern, a few turns per screw, until firm resistance, not gorilla-tight.
- Plug the fan into the CPU_FAN header, many boards refuse to boot without it.
Step 4 – Verify with numbers
Boot, open HWMonitor or the BIOS hardware page, and check idle temperature (roughly 30 to 45 degrees for most desktops). Then run a ten-minute stress test: modern CPUs happily sit in the 70s and 80s under full synthetic load. What you are looking for is stability, no instant spikes to 95+, which would mean poor contact.
Paste is cheap, cooling is a system
If temperatures stay high with a perfect mount, the cooler itself is undersized for the chip, or the case airflow is starving it. Our tested best CPU coolers and best air coolers guides cover upgrades for every budget, and the low-profile coolers roundup handles compact builds.
Frequently asked questions
How much thermal paste should I use?
A pea-sized dot (about 4mm) in the center of the CPU is right for most desktop chips; large chips like Threadripper take a bigger X pattern. Too little leaves dry corners, but far more people over-apply: excess paste squeezes onto the socket and actually insulates edges. The mounting pressure does the spreading for you.
How often should thermal paste be replaced?
Quality paste lasts 4 to 7 years in a desktop. Replace it when you remove the cooler for any reason (never reuse the old squished layer), or when idle and load temperatures creep up 10 degrees or more over their historical norm with clean fans and unchanged settings.
Did I apply it wrong if my temps are high afterwards?
Recheck three things: the plastic film was removed from the cooler base (the classic), all mounting screws are tightened evenly in a cross pattern, and the fan is plugged into the CPU_FAN header. Uneven torque tilts the cooler and leaves half the die barely touching, which shows up as instant 90 degree spikes.
Clean base, centered pea, even cross-pattern mounting, and a five-minute stress test to verify. Thermal paste is a two-minute job that people only get wrong by overthinking it.
