so im building a pc and i found this ram that is clocked at 2400
would i need a motherboard that is compatible with that..
RAM : http://www.newegg.com/Product/Product.aspx?Item=N82E16820231585
MOTHERBOARD : http://www.newegg.com/Product/Product.aspx?Item=N82E16813130637
It will work, it'll just only work at the speed the motherboard can support, therefore pointless spending the extra $$$.
A motherboard which supports 1333mhz RAM will run 1866mhz of RAM for instance but it will only run at the speed the MOBO can support i.e. 1333mhz.
Hope that answered your question.
Not only that, but depending on your CPU, it really isn't even necessary. The most recent FX processors from AMD only support up to 1866, and the 3570k only supports up to 1600. I'm not sure what i7's support.
Toast has a good point. I am running an i7 3770k right now. It supports my 2133mhz ram just fine (although I'm not quite sure what the max speed an i7 will support is). Better not to waste money on a part when it won't be at it's full potential.
SInce you have an am3+ board there, I'd suggest G.Skill Ares. It has a great price right now on newegg. with the promo code. I picked up 2 4g sticks for only 40 bucks, and it's 1866 with a cas of 9. I might try setting it to 1600 with a cas of 7, as I've read this is possible.