What is the ASM Performance benefit in setting up the disc groups for Data and Index separately? Ca

I am setting up a new ASM based environment for a Hybrid database.

In our current setup we separate the Indexes and Tables in its own tablespace, data files and file systems for performance.

I am reading this is not needed in the ASM environments as ASM manages the asynchrounous IO within itself. But want to confirm and compare the performance bench marks if they are available somewhere.

So to be specific, If i have 3 ASM discs, is it better to create one disc group and place all table and indexes in that DG?

Thanks,

Senthil. G