isa 20+4 pin psu compatible with a mobo thats 24-pin?

The easy answer is, probably.

I just did a quick google, and some PSUs that say 20+4 come with BOTH a 20 pin connector as well as a 24pin. Then I found another one that said it as 20+4 but it was a little different. It came with a 24pin that included a 20 pin adapter. Then there was a third type that also claimed to be 20+4 type. It was a 24 pin connector with a removable 4pin!

Anyways it SOUNDS like you should be fine either way, but if you want to be sure, give us your motherboard make/model as well as a link to the PSU you are talking about.

its pretty good...do u also know where i can find the thread thats a guide to good psu vs bad psu's?
antec psu
heres the mobo its currently out of stock but ill get it from some other retailer

I had an ECS 915P-A, and the 20 pin cord on my PSU worked fine. The only thing I noticed was a ! on BIOS POST that said only a 20 pin connector was being used, but everything worked well. My current PSU has a 20 pin, and my ASUS P5P800 mobo is 24 pin; I just got a 20/24 pin adapter from Newegg at about $3, and all is well.

uea..buy my psu's pins are 20+4 not 20

Just looked at the pic in the link from your first post, and it looks like that +4 piece is removable from the main cable, if need be. The mobo you shoiwed is 24 pin, so that Antec oughta be fine with it. A lot of the newer mobos are 24 pin, many of the older, and many of the newer, as well, are 20 pin. I think PSU mfr's are just making themselves compatible with either. ( I have an Antec SmartBlue 350W in another system that works great, very stable. Others will tell you that Antec is middle-of-the-road in reliability--I think they're great.)

Here you go:
http://www.hardforum.com/showthread.php?t=792566

merci beaucoup