Hello,
If you are talking about EPS cables for the CPU, only the 1 8-pin connector is needed. You will only get a benefit out of an additional EPS connection when doing extreme overclocking, when the CPU is being cooled by LN2. SO it is not likely many will need this.
Now, if this is AUX power for using multiple GPU's configs, you would just use one of the PCI-E cables provided, not EPS.
Let us know if you have any further questions, might want to call your manufacture to ask what the cable is directly for and if it is needed.
If it is CPU stability you are concerned about, it is likely just an adjustment to your OC settings you need to make to get what you want if it can do it.