Regaurding videocard ram speeds

[MiranoPoncho]

I noticed a funny little quirk, in the fact that no matter if one is to buy a geforce mx 440 at 400mhz ddr(200mhz) or if someone is to buy a 7800gtx @ 1300mhz gddr3, they both clock to half of thier specification, regaurdless. This is confusing to me sience looking after the ddr2, they only have to be one quarter, as for being quad pumped. I say, does the number indication mean an increase in speed or merley a new technological test bed?