Yes your are going to see those kind of temps difference with those programs. There are couple of different temp sensors on a cpu for temps readings. So dont be alarmed. Its nornal. I use Coretemp and Everest to get my temps readings for my cpu and gpu. Your idle temps look ok.
What are your temps at load using Orthos or runing dual Prime95?
This is a problem. Some people are overclocking and thinking their temps are ok, and they are not.
I use TAT (Intel thermal analysis tool) and coretemp. They only differ by 1 degree at the most on my system.
However my Gigabyte bios and Gigabyte hardware monitoring software (easy tune 5?) both show the temperature much, much lower than what it really is.
Similar problem here with a Gigabyte DS3 mobo. Easy Tune & Core Temp have the same readings, and TAT is about 10°C higher.
I use Everest Ultimate. It reads the individual temperatures for each of the cores on my CPU. They're usually within a degree or two of each other. At least for my CPU/mobo combo the "overall" CPU temp is WAY off. No matter what I do (idle/full load) the "overall" temp is 35C +/- 5 for some reason. I've found that these temperatures are about the same as those reported by Speedfan, but I like Everest because it tells you so many other things about the computer.