A lot of things affect that temp- the ambient temp, the case airflow, the HSF. You did not say if you had replaced the case, motherboard, using stock heatsink,etc. I looked at your specs but cannot tell about your cooling setup.
42 C is OK, what you should also test is temps under a load, that is what will be real important. When everything starts warming up, and you are approaching 70C, time to reassess and make some changes in your cooling.
1. Do you have an exhaust fan besides the PSU fans?
2. How is the airflow? Ribbon cables hanging in the path of the airlfow?
3. Integrated graphics such as you have will heat up a MB, which will in turn heat up a CPU.
4. Good luck and enjoy your new CPU. Any plans for a new MB and video card?