CPU temp monitoring.


Senior member
Nov 9, 2009
Hello everyone, I've been doing a bit of reading lately and I'm still wondering....why does the BIOS temperature monitor for my motherboard always read higher than software temperature readings, such as ones from OCCT 3.1? I've been reading saying that they take temperatures from different places. Apparently the BIOS takes it from the CPU socket and stuff like OCCT takes it from the CPU core itself, which should be cooler since it is being cooled by the CPU cooler?

Clarification would be nice. I'd hate to find out my CPU temps I've been getting in OCCT were 15 C lower than they really were.


Diamond Member
Jul 7, 2008
First off, I heard from another poster here that having the BIOS open actually puts a load on your processor and will therefore show a higher temperature than if you were just to look at a monitoring program on your desktop while idling.

Second, yes, your computer most likely contains two different temperature sensors for your processor. A simple way to distinguish the two is if you have a dual-core or a quad-core CPU, there is the "general" Tcase reading which is a single temperature probably the one shown in your BIOS (so, the CPU socket you mentioned). Then there is the "individual core" Tjunction sensor that will show multiple temperature readings, one for each core. These two types of sensors are almost always different from each other and they operate considerably differently.

What OCCT is showing you are the Tjunction readings for each core. On most processors - or on my processor, at least - the Tjunction reading is usually higher than the Tcase reading. I think the Tcase reading is supposed to be more accurate because it reads the temperature from the CPU where the heat disperses, and not inside the actual CPU. Someone can confirm/correct me on this though. Of course, the idea that Tcase should be lower than Tjunction is in spite of the fact your BIOS reading is actually higher than your OCCT readings, but like I said, I think the BIOS actually puts somewhat of a load on your CPU, so it would make sense.

It would be very helpful if you posted what kind of processor you have.

Also, get a hardware monitoring program that can show temperature readings from both sensors (I recommend SIW). The Tcase sensor might be shown as TMPN0 or TMPN1 or something like that, so just make sure you're looking at the right one.
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May 22, 2007
often the reason is that tjmax is set at a different number. most current software readouts (real temp, core temp, speedfan, etc) use a default number of around 100c for this. so if your temp monitor displays temps of, say 80,77,73,74, it's really saying a distance to tjmax of 20,23,27,26. I tried having my system display distance to tjmax for a while, but it just made my head hurt. I now keep it at 100c and have it display the "real" temperature.

168 pages of explanation
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