RAM abbreviations misleading, please clarify

(EDITED*)

Hello, I am finding two different refrences as to the meaning or tag at the end of numbers concerning ram memory.

This is how ive come to understand it.

Example:
DDR2-800 = PC2-6400 (just corrected)
Now the only number i have found that pertains to the standard name(DDR2-800) is the data rate (800MT/s) not MHz... The I/O bus clock which is measured in MHz is listed at 533MHz.
So why is it everywhere i read people list DDR2-800 as DDR2-800MHz?

My processor is listed at 533MHz(fsb) which should mean that my possible data rate(MT/s) would be 1066

I am seeing ram chips listed as PC2-6400 800MHz, that doesnt make any sense. the 6400 has a MHz of 400 and a MT/s of 800

My RAM is listed as DDR2-800MHz how is this possible when my processor is only 533Mhz.

I just need someone to clear this up, i have limited knowledge of this subject i am only trying to find out how to upgrade my netbook.... because it sucks.

actually i think i just realised that the FSB has nothing to do with the RAM? i have to look up the motherboard? stupid anyway why wouldnt they just add that as information in the computer. anyway.. just type "Yes." if this last part is right. Then ill know not to expect any answers.

400mhz x 2 (Double data rate or DDR) = 800mhz ram (PC6400)

The fsb of your cpu does not have bearing on the ram. Meaning you don't need 1066mhz ram for a 533mhz cpu. 1066mhz ram runs at 533mhz x 2 (DDR) = 1066mhz.

You can run your 533 fsb cpu with 800mhz ram (PC-6400) just fine.

What cpu do you have?