Do you mean ATX version of wattage?
If your refering to ATX version, pretty much every motherboard from the last 4 years or so has been ATX 2.x the main difference here is that it connects to the motherboard with e 24pin connector as opposed to a 20 which was found in ATX 1.x
Every ATX 2.x PSU I've seen has a detachable block on the mobo connector so you can connect them to older boards.
If your refering to ATX version, pretty much every motherboard from the last 4 years or so has been ATX 2.x the main difference here is that it connects to the motherboard with e 24pin connector as opposed to a 20 which was found in ATX 1.x
Every ATX 2.x PSU I've seen has a detachable block on the mobo connector so you can connect them to older boards.