guys, what's the difference in using those types of cables? because i have a GTS250 that works fine with the 6-pin to 1x 4-pin connector to the power supply i was just wondering if it has any difference if i used the 6-pin to 2x 4-pin connector?
There is no difference at all, they are both 12 volt connectors. In fact, all the wires coming out of the power supply are 12 volt except the motherboard connector which is about 8.0 volts. The six pin connectors have current to power small circuit boards that do not regulate their own current, like a SATA hard drive and 4 pin connectors are simply 12 volt conveyers for things like system fans and older IDE hard drives.
In theory the 6 pin connector will give more stable current, but in practice it rarely makes a difference.