AB9 Ram

I have an Abit AB9 motherboard and 1 gb (2x 512MB) of patriot extreme performance ram. I want to get some more ram I was wondering if I can just slap in some corsair ram (another 2x512MB kit) and call it a day? Also, I saw some awesome crucial ballistix (2x1GB kit) at ddr 1000. Can I throw that in with the patriot memory that runs ddr 800?