I’m researching the D945GCCR intel motherboard, and the manual says this: <blockquote>For LAN wake capabilities, the +5 V standby line for the power supply must be capable of providing adequate +5 V standby current. Failure to provide adequate standby current when implementing LAN wake capabilities can damage the power supply. </blockquote>

I just did a search on this subject: “+5 V standby current power supply”, but actually a better search term is “5VSB”:

ATX Power Supply Power-On Switch - this page is actually very helpful! It explains how the power on switch works.

Finally found the wikipedia page on power supplies, which had these helpful tables:

24-pin ATX power supply connector (20-pin omits the last 4: 11, 12, 23 and 24)
ColorSignalPinPinSignalColor
+3.3 V113+3.3 V sense
+3.3 V214-12 V
Ground315Ground
+5 V416Power on
Ground517Ground
+5 V618Ground
Ground719Ground
Power good820-5 V
+5 V standby921+5 V
+12 V1022+5 V
+12 V1123+5 V
+3.3 V1224Ground

Also found this interesting but unrelated page:

How to Convert a Computer ATX Power Supply to a Lab Power Supply