i7-12700K Ran Without Thermal Paste for 3 Years and Hit 100C in OCCT [2026]

By Indie Kings | September 19, 2026

Updated September 19, 2026: A prebuilt PC with an Intel Core i7-12700K ran for three years without thermal paste between the CPU and AIO cooler and still booted, per the owner's Reddit post relayed by VideoCardz. The system hit 100C under load once the missing paste was found and an OCCT stress test was run.

Intel Core i7-12700K installed in LGA1700 socket with AIO cooler removed showing dry heat spreader

Image: The i7-12700K heat spreader after the AIO cooler was removed, showing no thermal paste. Credit: u/MohakAoki via VideoCardz.

What happened with the i7-12700K and missing paste

Per VideoCardz coverage of a Reddit post by user MohakAoki on r/pcmasterrace, a prebuilt system shipped with a Core i7-12700K and a dual-fan AIO cooler but no paste on either surface. The owner said the system ran this way for three years since it was built.

The discovery happened only after the owner opened the system and removed the cooler for inspection. The copper cold plate and CPU heat spreader were dry. Most AIO coolers ship with pre-applied paste, so the miss likely happened during assembly.

VideoCardz dated the report September 17, 2026. The owner documented the find with photos and a follow-up stress test result.

Why the PC still ran without paste

An AIO cold plate still makes direct metal contact with the CPU heat spreader even without paste. That contact transfers some heat, just inefficiently. This partial transfer can keep a system from shutting down immediately under light loads.

Thermal paste exists to fill microscopic gaps between the two surfaces. Without it, air gaps insulate portions of the interface. The CPU then runs hotter but can stay under the shutdown threshold when idle or lightly loaded.

Intel Alder Lake chips like the i7-12700K also throttle aggressively before shutting down. The processor reduces clocks as temperature climbs, which lowers heat output and can keep the system limping along for years in desktop use.

How hot it ran and what OCCT showed

After finding the bare surfaces, the owner ran OCCT, a CPU stress test. Per VideoCardz, the i7-12700K quickly hit 100C. That is the chip's thermal junction maximum, where throttling is expected.

The report notes the AIO fans were set as intake, with the radiator mounted at the front. Depending on case airflow, that layout can restrict throughput, but the owner and VideoCardz note paste was the primary issue, not fan direction.

A paste-less interface also explains why gaming and heavy workloads would have triggered throttling. Light browsing and idle would look normal, which is why the problem went unnoticed for so long.

Expected temperatures with vs without paste on i7-12700K

Condition	Typical load temp	Notes
With quality paste and 240mm AIO	70C to 85C under OCCT	Depends on ambient, case airflow, and fan curve
Without any paste, same cooler	99C to 100C quickly	Immediate thermal throttling, per this report's OCCT result
With dried or poor paste	85C to 95C	Higher than normal but often below throttling

How this happens on prebuilt PCs

Most AIOs ship with paste pre-applied to the cold plate. Assembly requires either leaving it alone or cleaning it and applying new paste. VideoCardz notes it is unclear how the factory missed both, but a plausible path is that someone wiped the pre-applied paste intending to use higher quality paste and forgot to reapply.

Prebuilt QC varies by builder. Some builders include a burn-in test that would catch extreme temperatures. Others rely on a quick boot check, which a paste-less system can still pass at idle.

The i7-12700K is a 125W base power Alder Lake chip with 8 P cores and 4 E cores. At full load without effective cooling, it can exceed 180W. That makes missing paste more visible under stress but easy to miss at idle.

Steps if you suspect missing or bad paste

Check BIOS idle temperature after a cold boot. Idle above 60C at 22C ambient is suspicious.
Run a short OCCT or Cinebench load for 2 minutes and watch the max temperature.
Power off, remove the cooler, and inspect both surfaces before cleaning and repasting.
Apply a pea-sized dot of quality paste and remount with even pressure.

What to check on your own PC

Check your CPU temperature first before opening the case. Use HWInfo, HWMonitor, or BIOS readings. You want idle and load numbers, not a single snapshot.

If your system hits 95C to 100C under moderate gaming loads with an AIO, repasting is a cheap first fix. Good paste costs less than most fans and often drops temperatures by 10C to 20C.

When you do open the case, note fan orientation. Front radiator as intake can work, but ensure exhaust exists elsewhere. VideoCardz relayed that this system's AIO fans were set to intake, which is common, but airflow balance still matters.

Idle check: 30C to 45C is normal with an AIO at room temperature.
Gaming check: 65C to 85C is typical for i7-12700K in games with proper mount and paste.
Stress check: Sustained 100C in OCCT with clean fans points to mount or paste problem.

FAQ

Can a CPU run without thermal paste for years?
Yes, as this case shows, but it runs hot and throttles under load. Light use can hide the problem for a long time.

Did the PC need new hardware?
No. Per the report, cleaning and applying fresh paste and correctly remounting the cooler resolved the thermal issue.

Is 100C dangerous for i7-12700K?
100C is its throttling point. Brief spikes are expected in stress tests, but sustained 100C indicates a cooling problem you should fix.

Do all AIOs come with paste?
Most ship with paste pre-applied to the cold plate. If you remove it, you must apply new paste before remounting.

Could intake fan setup cause this?
Intake versus exhaust changes case airflow, but missing paste is the dominant cause of the 100C result reported here.

What paste should you use?
Any reputable ceramic or carbon-based paste works. Apply a small dot and let cooler pressure spread it, or follow the cooler manual's pattern.

Bottom Line

A Core i7-12700K survived three years with no paste because dry metal contact and aggressive throttling can keep a PC alive at idle. Under load the flaw is obvious, as the 100C OCCT result showed. If you bought a prebuilt and never checked temperatures, a quick thermal check and repaste is cheap insurance.