schwag91 - Are you still here?
I was just over at Xbitlabs reading a technical review of 7 Antec power supplies. Here is a direct quote about +12 volt rails that might interest you:
"The Antec website claims that two +12V lines (one of which is connected only to the 4-pin ATX12V connector) ensure stable power for the CPU that does not depend on the consumption of the other components. As I have repeatedly noted in my reviews, this is untrue. There is but one 12V power rail inside the PSU. It is split into two lines at the output in order to make the PSU safer for the user. Thus, there is no talking about the two lines being independent. Except for the tiny difference due to the voltage drop on the wires and connectors, the voltages of the 12V1 and 12V2 lines are almost identical. If one sags, the other sags, too."
You can read the entire review at:
http://www.xbitlabs.com/articles/coolers/display/antec-psu-roundup.html