My board just went from AA which is normal to 30 then looked it up in the manual that says to be used later? Everything seems to be running fine, should I worry?

If anyone could throw some in site on this, pretty noobish question. I only see 4pin connectors on the Mobo and I read that the 3pin connecters will fit just fine is this true? I thought I tried it earlier on but didn't think it would stay. This is t...