Not going to single out posts... just add my pennies to the pile

1) A 24-pin PS that has seperate wires going all the way back to the PCB in the PS IS a 24-pin PS. It is not a "re-treaded 20-pin supply".

2) On the issue of seperate +12V rails - this is about compliance with certain governmental regulations in various locals and has nothing to do with a PS being a 24-pin PS nor with it meeting the requirements of a ATX 2.0x supply.

3) The extra 4 pins on a 24-pin PS is not just about current carrying capabilities and/or extra pins. It also involves issues of parasitics in the power distribution system for your MB and add-in cards... including IR drop, inductance, frequency response, and noise. It also has to do with compliance to the ATX 2.x specs. And it requires seperate connections all the way back to the PS.

4) Based upon my own design experience, there are valid reasons why DFI is requiring true 24-pin PS's. See comment 3.

5) It is possible with a good 20-pin PS to create the equivalent of a 24-pin PS using a 24 to 20 pin adapater - it's done by cutting the wires between the extra four pins of the adapter at the point they join the standard 20-pin power pins and connecting the now unconnected 4 extra pins' wires all the way back to the PS's PWB with their own seperate wires. One way to do this is to use one of the SATA power connectors, which has all 4 required connections (+5,+12,+3.3,Gnd) and seperate wires all the way back.

6) I initially ran my DFI NF4 with a 20-pin PCPnC 450ATX supply without any problems on my bench (although in a stripped system configuration). But... it did hinder the performance. Whether or not a 20-pin PSU can work depends on the PS, what other components are in the system, and how close to the edge you intend to push your system.

So in regards to can you use a 20-pin PSU... given certain conditions, yes. Will it provide you with the most stable, overclockable system without at least modification as discussed in comment 5....NO. Does DFI know what it's talking about making a 24-pin PS a requirement...YES! For much the same reasons, plugging the extra MB power connectors into your PS is also recommended.

By way of a recent experience (one of many, many, many dealing with power and power distribution issues I've seen), maybe you'll understand DFI's stance on this issue....

On a project I'm working on at work, we had performed exhaustive testing on some new hardware and it had performed flawlessly in our development test environment. When we did a manufacturing run of the item in question, they were "failing" during manufacturing testing. I ended up during a 72 hour period, with only two 3 hour stints of sleep intermixed, in the manufacturing facility tracking down WTH was going on (and then lending a helping hand to testing to meet our deadline). To make a long story shorter, the problem ended up being someone who thought they could disregard the guidelines I had given regarding the power distribution in the test setup and used single wire connections between the test station power supplies and the test adapter for power distribution, along with improper power distribution inside the test adapter. The net result was perfectly good products with excellent margins "failing" test and my aforementioned grueling 3 days isolating, identifying, proving, and fixing the test setup they were using so that it conformed to the initially stated requirements. Afterwards the batch of product passed all testing with flying colors and substantial margins and are now being happily used by the customer

Oh... one last comment... it is *possible* under certain conditions for what the OCZ rep said to occur...