corsair cmx4gx3m1a1600c9 showing only 665 hz

[ANINDYA_50]

why my cmx4gx3m1a1600c9 showing only 665 hz

 

[cin19]

1) depends on what CPU and MB do you have? Like 3rd or 4th gen intel cpu that will support the 1600MHZ speed.
http://ark.intel.com/products/65693/
2) Or you have to go to the BIOS, in the the RAM section set up "XMP profile" if the MB has this feature and cpu/MB does support it, or manual set to 1600Mhz if cpu/MB does support it.