Repasting or cleaning can help when the old paste had dried out or dust blocked the airflow. On a machine whose cooling was fine, it may change nothing.
- Run the same test before and after, under the same conditions, ideally more than once each time.
- SystemCheck's report compares the current run with the last saved run on the same processor, figure by figure. Judge a small difference against the run's own interval, shown in the figures table and the repeatability section.
- A browser reads no temperature. A sensor log before and after shows whether the chip runs cooler, which can matter even when the score does not move.
The short answer
Measure before you open the machine, measure again after, and compare like with like. If the sustained part of the curve holds higher or slides less after the work, the repaste or clean paid. If the difference is within the run-to-run noise, it did not change the performance you can measure, though it may still have lowered temperatures or fan noise.
Make the two runs comparable
Most before and after differences that look large come from changed conditions, not from the paste.
- Same power source and power mode, same surface, same browser and version.
- Start each run from the same state: after the same idle break, with nothing else open.
- The same run type both times. A Deep run gives the cooling longer to show its limit than a Standard run.
- The same room if you can. A warmer room raises every temperature.
- Repeat each side at least twice, so you know how much a run moves on its own.
Reading the difference
Look at the settled part of the curve, not the first seconds. The boost at the start is short and mostly set by the chip's power limits, so a cooling change shows best in how high the level holds after settling and whether it keeps sliding. The report's before and after section shows this run against the last saved run on the same processor, and it adds a note when a stage reads unusually against the runs saved before. It does not decide what counts as noise for you: every figure carries its interval in the figures table, and the repeatability section shows how far a repeat moved, so read a gap smaller than those as no change rather than as an improvement.
A sensor tool such as HWiNFO on Windows, run during both tests, shows whether the chip now runs cooler at the same load. A lower temperature with an unchanged score is still a result: it means the chip was not at its temperature limit before, and has more margin now.
Terms used here
Questions
- Does repasting a CPU improve performance?
- Only if heat was the limit. When old paste had dried or a fan was clogged, the chip may hold a higher level for longer afterwards. When a power limit or the maker's settings were the ceiling, cooler running will not raise the score.
- How soon after repasting should I test?
- Some pastes are described by their makers as settling over the first heat cycles. A fair approach is to test once straight away and again after a few days of normal use, under the same conditions.