When I first built my older system using my OCZ Stealth 600W and my CM 690 case, both the 24-pin and 4-pin cords were too short. I bought two cords at
PC Cables: DB9, DB25, IDE, PS/2, mouse, null modem, SCSI, serial ATA, printer cables - Cables To Go and the problem was solved.
Even since I have changed out my motherboard, I still use the extensions because it gives me more options for routing behind the motherboard tray.
Cheers!
Lunch_Time_Canuck :)