Hi Shifali,
For SAP MDM 7.1 you should have min 8 to 12 GB RAM, almost 100 GB harddisk. However the MDM performance is depends on various other factors like your business and technical aspects, like number of users, no. of repositories, records and other applications running on it which collectively puts load on the underlying server. you can also refer to the MDM sizing document available in help portal.
regards
mohan