Even distracted pros can make a rookie mistake. And no one here knows a posters' level of expertise or their experience so don't take offense if something suggested "sounds" condescending. We are just trying to help you help yourself - that means we need to ask questions, and not assume you are a pro.
Once TIM (thermal interface material) has been applied
correctly "once", it should
never need replacing again except when the cured bond between the heatsink and processor is broken. And that should be a very rare event too and would only happen if the entire case is abused (dropped or bounced during transport) or when the user removes the cooler, or sadly, when the user twists the cooler too hard to see if loose, breaking it loose in the process. Otherwise, unless that cured bond is broken, TIM will easily last many many years (10, 15 and longer!) and not need replacing just because x number of years has passed. The only reason TIM comes in a liquified format is so we can squeeze it out of the tube and spread it evenly across the die in a smooth layer. So even if it dries, the solid particles (the "active ingredients", if you will) left behind are still doing their job.
If a processor "
needs" the few degrees of cooling a fresh application of TIM "
might" provide to prevent crossing thermal protection thresholds, there are bigger cooling issues to deal with first.
That said, you say "several times" - did you
thoroughly clean the mating surfaces of old TIM before applying new TIM?
Also, it is important to note that the purpose of TIM is to fill the microscopic pits and valleys in the mating surfaces to push out any insulating air that might get trapped within, and to prevent any insulating air from getting back in. The most efficient transfer of heat occurs with direct metal-to-metal contact. Therefore, any excess TIM is actually in the way and counterproductive to that heat transfer process.
So, did you ensure your TIM application was as thin as possible, while still providing complete coverage?
Also, it is important to note it is the case's responsibility to provide a sufficient supply of cool air flowing through the case. The CPU cooler need only toss the CPU's heat into that flow.
Typically, you want good "front-to-back" flow through the case. Are we dealing with
this AeroCool Rift case listed in your specs? According to the specs, it has excellent fan support
but only comes with a single 120mm fan in back!
That's not good enough - especially with a bottom mounted PSU that has its own intake and exhaust vents.
Did you [hopefully] add more fans? What fans do you have and how are they oriented?
If you only have 1 or 2 120mm fans, that might be your easy to resolve problem. Add another fan to increase that desired front-to-back flow of air through the case.
