Is there any way of moving these during a project? This is the first time I've used Premiere for anything long enough for it to be an issue and I didn't realise that they defaulted to the c drive. So can I move them during a project and if not, how can I set up Premiere to put them where I want them in future?

ETA: I'm on 5.5 if that's relevant.

One of the options is to specify the default location of these files - I keep mine in the project folder - it's up to you really.

Edit > preferences >media and browse to new location. IIRC when I did this once and there were cache files present ppro asked if I wanted to move those files to the new location.

If I am not mistaken these files are used by the other Adobe apps that link to premiere, so you are changing the default for them as well.

You are correct, Battle, all the Adobe programs related to Premiere use a common location for the cache - move it for one and it moves for all. It pays to have this media cache on a separate drive to your media, and a fast one too.

I have stored Media Cache files on a large capacity External Harddrive. As the Media Cache files are very small I am thinking that the 500 GB ext. drive is wasted. Would a Flash Drive (Memory stick) be suitable for the storage of the Media Cache files working with CS 5.

Roy,

All storage devices, with the exception of SCSI drives, are half-duplex. That simply means they have to wait for reading to complete, before they can write to the same device or, alternatively, wait for the writing to complete, before they can read. That is the main reason why multiple disks are advised to spread the load, read from one device and write to another.

Responsiveness of a system depends to a large degree on sustained transfer rates of the storage devices attached, the higher the sustained transfer rate, the snappier the system feels.

Typically you will see sustained transfer rates like this:

USB2: 20 - 25 MB/s
FW400: 30 - 35 MB/s
FW800: 55 - 60 MB/s
USB3: 80 - 100 MB/s
SATA: 120 - 150 MB/s (eSATA is identical)
Raid0: generally almost n (number of disks) x single disk transfer rates.
Huge arrays: up to 3500 - 4000 MB/s

A Flash drive (memory stick) is generally even slower than a USB2 drive, so this is ill-advised. Media cache files on a SSD are feasible if it is a non-SandForce based controller and you are willing to accept the life-expectancy degradation.