So, CPU-Z is reporting that my DDR3 1333 RAM is working at 665Mhz and is capable of running at 667Mhz max.
The RAM is made by Strontium (Dynet, Korea). This is what written on the cover of it : "EVM - Value Memory - Lifetime Warranty - Universal Compatibility - a value brand of Strontium." A sticker is placed aside the module itself and "Dynet 2GB DDR3 1333 - Korea" is written on it. and Dynet is engraved on the small black chips on it.
Nothing is wrong, it is simply Dual Data Rate RAM.
This means that the effective clock is twice the base clock by performing two data transfers per clock cycle.
In the case of your RAM, a 666.667MHz base clock (rounded to 667MHz) equates to a 1333MHz effective RAM speed.
I'm a little confused about what the OP is 'really' trying to ask.
The RAM is running at e.g. 665MHz, the 'Double Data Rate' is because the data cycle is both on the top an bottom of the Sine wave of the 'I/O Bus Bus' rate in other words two 'pulses' per single cycle. Effectively the RAM is running to the MOBO's Bus at 665MHz * 2 = 1330MHz in your case.
The 665MHz vs 667MHz variance is is due to the MOBO's FSB for AMD or BCLK for Intel variances, and 'SDRAM' Synchronized dynamic random-access memory meaning the RAM is 'Synchronized' to the FSB or BCLK so as the FSB or BCLK goes up or down so does the RAM's Frequency. The FSB or BCLK varies due to load and and technologies like Intel's SpeedStep and/or Turbo boost.
If you ran an application like Prime95 or other CPU intensive application then DRAM Frequency will go up and down a few MHz.
So the root 'cause' is the MOBO's FSB or BCLK fluctuations.