1) the first poster is incorrect. you CAN get performance increases from partitioning without multiple filegroups - sometimes vast improvements even. This would come from partition elimination during query execution.
2) the questions you are asking mean you have no idea about partition elimination. This is a VERY advanced and complex feature and you REALLY need to get a professional on board to help you out.
3) Note that partitioning is an Enterprise Edition only feature.
Best,
Kevin G. Boles
SQL Server Consultant
SQL MVP 2007-2012
TheSQLGuru on googles mail service