|04-13-09, 08:01 PM||#1|
Join Date: Jan 2009
Location: Lingshan Islands
How to Determine REAL +12v Amperage on Your PSU
I'd like to mention an equation that would let you find how out much amperage your PSU has on the +12v rail(s). The +12v rails are probably the most important rails on a PSU since they supply the power to the CPU and GPU. People usually overlook this part of a PSU, in fact they tend to just buy cheaper PSUs in general which will cause many issues.
If you look on the sticker, near the +12v area, you'll see the amperage of the +12v rail(s), and under that a power measurement in watts. Lets look at my PSU for example, the COOLER MASTER Real Power Pro 650W.
See, three +12v rails with 19A on each and beneath it 540W. This means the +12v rails combined generate 540W of power at max load. Since 540W is the +12v power, divide 540 by 12 to get the real amperage, don't do 19 times 3 since that gives you 57.
540W/12v = 45A - nice value by the way
19A + 19A + 19A = 57A
Why is that incorrect?
57A x 12v = 684W - this is a 650W PSU
NOTE: This does not have to be done for a PSU with a single +12v rail. Lets use the COOLER MASTER Silent Pro M 600W for example.
It tells you right there it has 40A of +12v power. If you have any doubts...
480W/12v = 40A
I prefer multiple +12v rail power supplies since they are more stable (generally speaking). Here is what I recommend you look for in a PSU.
Not good at math? Neither am I. Use a calculator!
Also check out my PSU guide.