No, that motherboard does not support 1600 MHz RAM by default. You need to overclock to get those speeds.
Your motherboard specs: https://www.asus.com/Motherboards/M4N68TM/specifications/
Also, overclocking your RAM wont really help, your computer is using a lot of virtual memory because you have so little RAM. The slow speed is coming from paging so much data to the hard drive.