x16 and x8 orangization

Solution
X8 and X16 are generally a reference to what your PCI-E slots are running at and have nothing to do with DRAM - your link is to a single 4GB stick of DRAM - if used by itself it would run in single channel mode
The x8 and x16 refer to data width, in bits, of memory chips used in memory modules. x16 is not often used; x8 is far more common.

Part number KVR667D2D4F5/4GI uses x4 bit width memory chips.

Please note that this 4 GB DDR2 module is fully buffered with ECC. It will only work in systems that accepts fully buffered memory, it will not work in computer that takes standard un-buffered memory.