I've had reasonably good result having a dedicated hd for my 3d apps.  I have the apps installed on an external hd drive.  Core components are stored on you C drive, while the bulk of content is stored on the external.

 

It makes for easier housekeeping.  My downloaded content is stored on one partition, primarily for backup.  My installed content is installed on another partition.  My resources, textures, brushes, obj files and so on are on a third partition.  I also have another partion that is hidden from the OS that stores my system backup.  My primary partion is for OS and virtual memory (cache).  This allows me to control how much space is needed for each aspect of my computing.

 

The primary benefit is when my system crashes, I can 'nuke' my system partion with a hard disk utility, use my recovery disks for the out of the box state, then restore my system from my hidden partition.  This allows me to troubleshoot Bios, HD, or OS problems.  The separate partitions makes it easier to run routine utilities on a regular basis quickly.  Also when I upgrade to a higher capacity hd , I clone the partitions in stages rather than one huge mondo process.

 

The bad part is when I have to re-install my plug-ins.  There are two Carrara directories, one on the root (OS) partition and a second one in the partition that Carrara is installed.  The manufacturer will specify what directory to install.  I normally leave a text document to my self for future reference when I run across a  problem.