Highest build that takes rc beta keys ?

What is the highest/best x86 non RTM build that can use (activate) a legit RC beta key. ? Dont want to use illegal activate methods. Have a second (kids/test) machine that i would like to run till march of next year or till I can save up more for another license. I know I can use the RC 7100 but as others mentioned its a bit buggy. Thanks

7300 i think mate

As far as i remember it is 7260

7260-x86
7232-x64