Hi,
According to the specifications the laptop only supports a maximum frequency''' DDR3 10600 (1333MHz)''' RAM.
The '''maximum supported RAM is 4GB'''. As there are two memory slots it can either be configured as
1 x 4GB or 2 x 2GB.
If you use both slots to achieve the maximum of 4GB then the RAM will always operate at the lower frequency if the modules are of different frequencies and are at or below the maximum supported frequency.
You cannot increase the RAM to 8GB because it is not supported by the BIOS.