Originally Posted by Chozart
My post was not meant to compare the Antec NeoHE with the FSP. Sorry if it seemed like that. I just was confirming the fact that ~550W PSUs are not up to the task by stating that the Antec NeoHE is the only one in that power range to be Crossfire Certified, and that the reason is because it has exceptionally powerful 12V rails for a 550W PSU.
However, to make a fair comparison of the 12V rails, we also need to take the TOTAL available power on those 12V rail. The FSP can deliver 680W on the 3.3V, 5V, and all 12V rails. The 3.3V and 5V rails take up to 155W. Thus, in the most extreme situations, between 525W and 680W is available for the 12V rails. This translates into 43.75A and 56.67A for the combined 12V rails. The real available power likely is around 50A (depending on the draw on the 3.3V and 5V rails).
The story of the Antec is slightly different: Here, there is 504W available for the 12V rails, thus 42A. However, this can decrease when there are heavy loads on the 3.3V and 5V rails (remember, the PSU is only 550W). With a full load on the 3.3V (79.2W) and the 5V rail (100W), there is only 30.9A available for the 12V rails. Thus, I admit my information in the previous post was incomplete. A full load on the 3.3V and 12V rails will rarely occur, normally those loads are fairly light, and for all practical purposes the actual available power will be close to the posted 504W (42A).
Obviously, the FSP is the more powerful PSU.
I think that you are also forgetting that the first rail is always used soley for the First CPU. That means whatever amps are left on that rail after the first cpu/core gets its fix, you loose them.
At least I think most PSU's are this way, its what I was always told.
That's why I like the single rails and the quad rails as solutions to future power concerns.
I'm a big fan of single rails myself after doing my own research.
I really like that Mr. Zippy one.
50amps on a single 12v rail with only 4/100's volt deviation from 10amps to 50amps. WOW! http://overclockers.com/articles1313/
Think about it, a single rail is the most dynamic. You'll never be in situation where you hve to move one thing to another rail and maybe in turn you won't be able to fill up other rails to there maximum, not enough here too much there, ya know?
You're guranteed to get your full money's worth of 12v amps on a single rail and that's why I think they are the best.
One man's opinion of course.