Vista upgrade vs Value ram

Any significant difference between ocz pc2-6400 vista upgrade 800mhz 1gb and ocz pc2-5400 Value Pro Series 1gb and can explain to me why the latter, which is slower, more expensive?

Performance memory simply sells faster therefore sees lower prices in general. You can buy a pair of 1gb DDR2 800 dimms cheaper then you can buy two 256mb PC133 simms. Why? That extra covers any vendor's overhead for caryying a particular type of memory.