Should PSCD run in a seperate instance?

Hi ,

We are on ECC 6.0 and planning to implement PSCD. We have very high volume of transactions say around 3 millions/yr.

I want to hear how PSCD in implemented in various organisations for example, same instance in ECC or running physically as a seperate system?

Any input will help us a lot.

Thank you

RG's

yogi