Originally Posted by NewAtOCing
AC INPUT 115/230Vac 10/5A 60/50Hz
Load +3.3V +5V +12V1 +12V2 +12V3 -12V +5Vsb
Maxload 25A 25A 19A 19A 19A .8A 3.5A
Maxpower [ 191w ][ 540w ] 9.6w 17.5w
[ 650w ]
That was spaced out all nice 2 seconds ago.
12v1 + 12v2 + 12v3 = 19A+ 19A +19A = 57 Amps
57 Amps x 12v = 684 watts
Total power for the 12v rails is stated to be 540 watts,
So, you can not load each of the three 12v rails to it's max amperage as the PSU will only supply 540 watts to the 12v rails conbined, not 684 watts.
And further, the total max power for all the rails is stated to be 650 watts, but if you add up all the various voltage rails that comes to 758.1 watts (191w + 540w + 9.6w + 17.5w = 758.1 watts), but again you can't run all the rails at their rated wattage because that adds up to more power than the PSU can supply.
So, if you put 38A (19A on each of two 12v rails) that's a total of 456 watts. That leaves only 84 watts (7A) for the remaining 3rd 12v rail.
The same scenario applies to the rails with other voltages. If they are loaded to the max, there won't be even 540 watts left for the 12 rails (650 - 191 - 9.6 - 17.5 = 431.9 watts, not 540 watts (much less 650 watts!).
See...........Marketing hype that confuses nOObs! "I've got a 650 watt PSU, how can that be a problem?" Well, it's possibly really only a 432 watt PSU!
And it gets worse........
That total power rating (650 watts) is established at some operating temperature, perhaps (as some PSU manufactures do) at a temperature that is just before the PSU bursts into flame! Not the condition were the typical user will be operating. Note that Antec, like many others, does not specify the temperature at which their specs are established.
And it gets still worse.......
When you start to get near the limits for a PSU, voltages can't be maintained. As amp draw gets near the limit that the PSU can supply, voltages start to drop. Yeah there's a wide spec for acceptable voltages for most components, but if you're overclocking to the limit, those voltage changes can kill stability.
When I was OCing I used a PCP&C 1 killowatt PSU to power the motherboard (basically the CPU) only (no video cards, no HDDs, no fans, no pumps, etc). I got 12.03 volts no matter what the overclock was. Overkill? ...probably. But I knew that when a OC was unstable, it wasn't because of the PSU!
When all is said and done, reading and understanding the specs and being aware of the fact that you get what you pay for will lead to a PSU that won't be a problem for your particular set up.Edited by billbartuska - 8/5/08 at 8:10am