- Separating the OS drive from the rest of data, hence in case of OS crash and reformatting the OS drive, you don't lose data or go in the hassle of backing it up.
- Performance gains, as partitions are smaller in size then one full HD, the seek time is shorter
- Having different File systems as per need for each partition.
- Improved data organization. etc.
For Windows 7 the minimum requirement for Hard disk space is 16 GB for 32 bit and 20 GB for 64 bit, but its better to keep a minimum 50 GB OS partition. In some forums it is recommended that the page file should be on a different partition, but after some research I conclude that one should move page file on a separate hard disk rather then the a separate partition. so keep the page file on your OS partition in case you don't have additional hard drive.
I recommend to divide your HD into 3 partitions. and use the 20-40-40 rule , like 20% for OS , 40% for Programs, and 40% for Data. . You can tweak this based on your Hard drive space and requirements, e.g one good partition scheme for a 500 GB Hard drive could be
- OS -- 75 GB
- Programs -- 200 GB
- Data -- 225 GB
There are many good partitioning tools available, Windows also offers Disk Partitioning. But if you want more advanced options here are few good Disk Partition softwares in the market.