Don't worry - you've got it all wrong
The speed of the processor is calculated by: Front Side Bus x Multiplier = Processor Speed.
When you are buying a faster processor, you are getting the same Front Side Bus (200mhz on all Socket 754 processors) but a higher multiplier, making a faster processor.
The processors Bus Speed is not 1600mhz, its 200mhz. The processors actual speed is 1600mhz
Just a tip - while thats a good setup, it supports AGP graphics cards only (the one type). So, if you plan on gaming, then its not good. However, while many people would save "It's Socket 754, it must be rubbish, get AM2 it's W00T!" if you just want to use the PC as a Sky+ box or just as a normal PC for work and a few games, Socket 754 is not totally dead and there are still cards being released for AGP which are very good