Making The Most Of Your Photoshop Scratch Disk

You can never have enough RAM for Photoshop and when that runs out it falls back on your hard drive to store data in. This is much slower than RAM – but there are ways to make this work as efficiently as possible.

Most peoples computers only have 1 hard drive installed, but Photoshop does not work efficiently with this set-up. This is because your operating system is also using this drive to store temporary information, Photoshop is pulling data from this drive and a whole host of other processes and application you have running in the background are also wrestling for access – obviously it doesn’t take a techie geek to work out that all this going on behind the scenes will not do Photoshop any favours when it’s trying to shuffle hundreds or even thousands of megs of data in and out of the drive!

The first step is to buy yourself a new hard drive – and buy the fastest you can afford. The factors to consider are rotation speed (7200rpm or faster), cache (8 meg or larger) and connection (SATA or ATA for internal, Firmware or USB2 for external – USB1 IS VERY SLOW). Size is not so much an issue for price these days, I recently bought a 200gig 7200rpm 16meg cache internal drive for less than the price of a good night out with the lady! I have got this partitioned into 3, the first partition for scratch disk, the second for data to be backed up and the third for my tilted of design elements.

Firstly – a word on partitions. It is a common misconception that if you have a single drive partitioned into 2, the first for system and the second for scratch disk you are getting the most out your system – THIS IS WRONG! The drive still only can shift a certain amount of data through the connection and this can actually reduce performance as the drive has to whip around all over the disk!

It is, however, a good idea to keep a completely clean partition on a separate hard drive for scratch disk. This makes it easier for Photoshop to find big, unfragmented areas of the drive to use as a scratch disk. For this reason it is a good idea to format this partition every few months or so to keep it in tip-top condition. Also, if you go for the kind of configuration I have outlined above DON’T be tempted to use this to store files you are working on, just keep it as a dedicated scratch disk and Photoshop will be happy! Finally, use the first partition, I have been told this will use the inner sectors of the disk which are more efficient than the outer sectors.

If you can afford it, a stripped RAID array will give the ultimate Photoshop scratch disk performance. This is basically a process where a computer sees a number of hard drives as one big drive – as your data is read and written it is split across all the disks giving you massive throughput of data – instead of the data all being forced down one cable to a single drive. This is a popular configuration for video editors for this exact reason. It can be expensive, but you will get much higher performance investing in 4 smaller, cheaper disks in a RAID configuration rather than 1 large disk. Mac OSX has software RAID configuration and control built in through disk utility, but Windows XP owners will have to invest in a third-party utility or hardware card to set-up a RAID configuration.