Again, that's not how it works mate, but you know what, i have explained this at least 20 times on this forum. It may be able to theoretically deliver 38A "the" 12V rail, but unless you have a true multi rail design (or a strong enough single rail) AND because they are limited by safety and ATX design standards, you can only deliver 20A on each rail max. Add to that, the fact that 12V+1 is dedicated to the CPU, and any unused wattage will be trapped, you are PRACTICALLY not actually able to deliver 38A, even if you use ohms law to calculate the max potential current via the method you described.
To clarify, it has 3 x 17A rails right. Using ohms law, you have calculated that it can deliver a total of 38A?
Well, consider the fact that 12V+1 is dedicated to CPU. A CPU uses what, 7A? That means that the other 10A (in this case) is trapped on the 12V+1 rail. So, even if you could add the other two rails, you would find that only 304 watts is available to the remaining system requirements. This means that in reality only 25A is available for the system to power everything other than the cpu.
That was my point.