Every modern cpu has the sensors for temperature monitoring, engineering samples, OEM or Retail.
I like to use a couple different monitoring programs for different reasons. However, I've found that if you start a monitoring program like HWMonitor 1st, it goes through and assigns each sensor with a value/identifier (< lack of the proper term). Now it's not reporting all of your hardware correctly, like 0 degree cores, but it is reporting other values correctly so you leave it running. Now you try a different monitoring program for your cpu core temperatures but it also reports them wrong. This is because the 1st program (HWMonitor) has already assigned the sensor an incorrect value and it's still in use.
You need to close any/all monitoring program that may be running and make sure there closed and not just minimized and hidden in the taskbar/notification area. Then try a program like CoreTemp
one at a time until you find one that works.
Or you should have a utility like Asus Probe on the cd that came with your motherboard or it looks like Asus has a new utility called Asus PC Diagnostics V. 1.10 that may work, ASUSTeK Computer Inc.