Whats the deal with 24pin ATX PSU connectors

I have just bought a Ultra Xconnect power supply 400watts to use in
conjunction with a AMD 3500+ and skt 939 board.

Here it is:
http://www.ultraproducts.com/product...roductID=3 04

It says it supports Pentium 4 and AMD CPUs and meets ATX version 2.03 and
ATX 12V version 1.2 specification.

When I bought it I thought it was the dogs ******** but now I see
motherboards with 24 pin PSU connectors and wonder what's going on.


Have I bought a lemon? Is it out of date? Has the ATX spec moved on?

Can you plug a 20pin ATX connector from the power supply onto a 24pin
connector on the motherboard and then use a 4 pin lead for the remaining 4
pins or would I need a convertor?


The motherboard I want to use it with has the following connectors:

24-pin ATX Power connector
4-pin ATX 12V Power connector

Would I need to buy extra cables / convertors to use it with this board?

Thanks

Pete