A repair technician remounted my CPU cooler last year but apparently did not apply fresh thermal paste. I still have the Corsair thermal paste tube I used at the time, and it has been capped ever since. Is opened thermal paste still safe to use after about a year, or should I buy a new tube whenever the cooler is removed? My Ryzen 7 9800X3D reaches around 95°C during multithreaded Cinebench runs and sits near 50°C at idle. Should I repaste it just to be safe?
3 Answers
An opened tube can last for years when it is capped tightly. If the first material that comes out is crusty, watery, or separated, discard it; otherwise it should work. A decade-old tube has still been usable for some people, although buying a fresh tube is inexpensive if you want maximum peace of mind.
Check the actual temperatures with a hardware monitor. If the paste is still smooth and comes out normally, a properly capped tube that is only a year old should be fine. Thermal paste is not like food with a strict expiration period.
You should normally apply fresh paste whenever you remove and reinstall the cooler, because the old layer can develop gaps. The tube itself does not need to be new, though—reuse it if it has not dried out or separated. Your 9800X3D reaching about 95°C in a heavy Cinebench workload can be normal because that processor may reach its thermal limit under sustained all-core load. Repaste it properly, then compare the temperatures afterward.
The paste still comes out smoothly, so I’ll clean the cooler and use it when I remount it.