I have the E45M1-Deluxe overclocked to 1.9GHz and my temps are stable between 30-50°C with just one case fan for cooling. (Wesena ITX5 chassis with Pico PSU and SSD)
That is the kind of temp range I would expect for this product.
If you are logged in, scroll down and look at the pictures.viewtopic.php?f=23&t=64999
I used that system with the fans unplugged before I installed the duct.
The CPU temp rose to about 50C-55C when idling on the desktop (drivers installed and power saving working) under both Windows XP and Windows 7 (note that the smaller of the 2 heatsinks is the one with the CPU underneath it - fan removed).
If that tiny pathetic heatsink can keep the CPU 10C cooler idling that the huge one on that motherboard then something is very wrong.
I would suggest as other people have done, install an OS, install the drivers, check to see (via CPU-Z) that the CPU clockspeed and voltage drops down automatically when idling on the desktop, and the monitor the CPU temps.
Also via CPU-Z check the BIOS/UEFI version against the latest version on ASUS's website and consider flashing the BIOS to the latest version if it is not already the latest version.
Finally to check whether the heatsink does not have enough pressure, re-test (from cold) with a couple of thick books balanced on the heatsink, turn the machine on and wait for its temps to settle at idle on the desktop, make a note of the temps, then remove the books, and look at the numbers further.
The added pressure might make a difference, but there will also be a loss of heat dissipation due to the books blocking the hot air escaping from the fins -either way the results will be informative.