Wolfyyie,
On behalf of Tom's Hardware Moderator Team, welcome aboard!
Although
mdd1963 and
geofelt have provided some helpful insights,
Mo99zh has provided some conflicting information, which you may no doubt find confusing. So in order to give you an accurate perspective, we need to point out that Intel desktop processors actually have
two thermal specifications.
geofelt mentioned 100°C, which is called "Tjunction". This is the "Core" temperature specification at which your
i5-4590S will "Throttle" (reduce Core speed and Core voltage) to prevent thermal damage. Since the heat sources are deep within the Cores where temperatures are highest, Core temperatures are the critical values. To further clarify, "CPU" temperature is a generic term that typically means "Core" Temperature.
Mo99zh mentioned 72°C, which is called "Tcase". This specification is highly misleading and has been confusing users since 2006. "Tcase" is
not Core temperature, but is instead a
factory only temperature measured on the surface of the Integrated Heat Spreader (IHS) where the cooler is seated and the temperature is lower. Users can't monitor IHS temperature because retail processors don't have this sensor.
Both Tjunction and Tcase specs are shown in Intel's "
Datasheets", which are detailed engineering documents that most users never look at. However, Intel also has a "
Product Specifications" website that's like a "quick reference" with which many users are familiar. This is where the 72°C spec originates that most users, as well as
Mo99zh find on Google and elsewhere on the Internet.
Unlike the Datasheets, the website only shows one
or the other of the two specifications, but not both. The spec that's shown is determined by the "Generation" of your processor. For 7th Gen and later Intel uses the Tjunction spec, but for 6th Gen and earlier Intel used the Tcase spec, which includes your 4th Gen i5-4590S.
Intel's intended purpose for providing a Tcase (IHS temperature) specification was primarily for developers of aftermarket cooling solutions. So for end users, this means the
Tcase is irrelevant.
Tjunction or "Throttle" temperature (also called "Tj Max") has
always been the
limiting thermal specification,
not Tcase.
Although most Intel CPUs Throttle at 100°C, it’s not advisable to run your CPU near its thermal limit. If your hottest Core is near its specified Tj Max Throttle temperature, then your CPU is already too hot. The consensus among well informed and highly experienced reviewers, system builders and expert overclockers, is that it's prudent to observe a reasonable thermal margin below Throttle temperature for ultimate stability, performance and longevity.
As such, this is the nominal operating range for Core temperature:
Core temperatures above 85°C are not recommended.
Core temperatures below 80°C are ideal.
Also, keep in mind that Core temperatures increase and decrease as ambient (room) temperature changes.
We have a Guide that covers this topic. It's a "Sticky" at the top of the CPUs Forum where you posted your question. If you look there you can't miss it, or just click on the link in my signature. We encourage our Members to check the Stickies as they often contain the information you need, which can save you time needlessly searching elsewhere for answers that might be inaccurate.
Once again, welcome aboard!
CT