You can partition from Windows 7 however the problem is you are generally limited to splitting an existing partition in half...which kind a makes the whole idea moot. There are several reasons to partition:
1. At home in your dresser.....do you have all your clothes in one drawer or do you have a socks drawer, underwear drawer, shirts drawer, pants drawer, etc. ? If you do, explaining the organizational benefit shouldn't be necessary.
2. Seek time - When you access a file, the OS has to search thru the entire MBR.....goes faster on a 64 GB partition than on a 2 TB partition.
3. Disk Speed - The outside of your disk is twice as fast as the inner edge. Forcing page and temp files to this area forever on a small partition at outside edge of disk as opposed to letting windows put them anywhere only means that performance decreases over time.
4. Formatting - NTFS file protections aren't necessary for temp / page files so lose the NTFS overhead and make this partition FAT32.
5. Wear and tear, backup - Is there really a reason to have your entire HD backed up every day ? After your last program was installed, why is there a need to backup the "Programs" partition ? Set the utility to back up OS partition once a week, temp / page file partition never, programs partition once a month, data partition once a day or whatever works for you
6. Wear and tear defrag - Is there really a need to defrag that programs partition except before installing a new program ? Set the utility's schedule to do once a month.....set the OS drive and data drives to a different schedule that works for you.
6. Fudged OS - What's easier to make an image of and restore an image .... a 64 GB OS partition or a 2 TB entire drive ? Wouldn't it be nice to fit that entire system restore image in a compressed file on a USB pen drive ? Try that with 2 TB of data.
7. Whose smarter you or windows - Ya know how windows and other defraggers claim to put your most used file at the beginning of the drive ? What's your most used file ? Mine is probably that 40 GB data partition backup that my backup software makes and puts it where I told it to way at the end (slowest part) of my HD.....I really don't want windows deciding that big fat file should be at the fast part of my HD.
8. Migration - moving from Windows 7 to Windows 8 and want a clean install ? Clone your disk to a new one, wipe the C partition (OS only) and install Win8 on newly formatted partition. All ya data, all your programs, all your special custom files for those programs are still there on Programs partition. Simply install the programs over themselves and all custom toolbars and customizations remain.