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watts is a unit of power. joule is a unit of energy. The relationship between energy and power is: Power = Energy / Time. And 1 watt = 1 joule / second So you need to know how much time it took to deliver/transfer that 2400 joules of energy. If for example it took 1 sec, then you have 2400 w. If it took 1 minute (60 sec) Then Power = 2400 J / 60 sec = 40 w
That would be 40x60 watt-seconds, also known as Joules, so it's 2400 Joules of energy. 3.6 MegaJoules is equal to one kilowatt-hour, also known as 1 unit.
120 v
Any of the dual-headed Radeon 2400-2600 cards should work fine. Size the OS with what you want the machine to do, a sever is what it is, not a gaming machine.
2700-2400/2400= 300/2400=.125 12.5%
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40% of 2400= 40% * 2400= 0.4 * 2400= 960
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