Dear Amrish,
HR professionals have a penchant for coining new phrases or terms. This has been happening for the last 30-40 years. What Personnel Management (PM) of the erstwhile era has become today's Human Resource Management (HRM). However, HRM of yesteryears is today's Human Potential Management (HPM) or Human Capability Management (HCM) and so on.
The latest craze is Human Resource Business Partner (HRBP). This could be yet one more phrase to stay relevant. While your question is about the difference between conventional HR and HRBP, I would like to say that it is a point to ponder as to why things have come to such a pass wherein HR professionals are required to say that they are "business partners". Why do Finance, Operations, Supply Chain, etc. professionals not say that they are business partners?
While HR professionals may say that they are from HR, however, in all practical aspects they still handle the issues of the PM of erstwhile times. Ask the average HR Manager what is it that he/she is doing differently from what Personnel Managers did, and you will not get a much different answer.
Check the prominent forums where discussions on so-called HR issues happen. If you find out the statistics of the queries raised on general points versus points related to PM versus actual HR issues, you will find that actual HR queries have the minutest percentage. This minutest percentage is nothing but the minutest difference between conventional HR and HRBP.
Thanks,
Dinesh Divekar