Running latest BIOS (5406).
It seems that the only program showing the PCH temp currently is "Open Hardware Monitor". Also "Open Hardware Monitor" and "CPUID HWMonitor" show a third sensor (shown as 51C here) which HWiNFO does not show. Please see the attached image (I have marked the sensors with color):
The missing value for Chipset temperature is due to a bug in the BIOS, which was most probably introduced in the new update.
Yes, OHM shows this value because it accesses the SIO chip (IT8665E) directly and this is a problem on 3xx/4xx series ASUS boards. There has been a lot of discussion about it on this forum. Result is - accessing the SIO directly can cause corruption of the SIO registers, which can result in a system crash, malfunction of fan control, inability to shut down the system, etc.
Hence ASUS made a WMI interface available to solve this problem and you can see that HWiNFO is using this.
So I don't recommend to use software that's not using the WMI interface on these series and rather contact ASUS to fix the missing sensor value in next BIOS version.
Martin, is it possible to force direct read from the SIO chip for test purposes? I am using OHM for at least 4 weeks and I didn't have a single problem (my PC is [email protected] 24/7). However if you use Asus AISuite simultaneously with HW monitor programs, problems arise...