Performance

CPU (Central Processing Unit)

The CPU is the heart of the computer. It is the electronic circuit that can execute computer programs. It's speed is the most important factor that determines how quickly you will be able to process image files. More and more computers incorporate multiple CPU's or have CPU's that have multiple cores, meaning that each circuit has two or more CPU's built into it.

Multi-core CPU's are somewhat more efficient than dual processors- which is why we are seeing more dual-core and quad-core, and even eight-core processors. In addition, they take up less space inside the computer which is why some laptops have dual-core processors now. In order to achieve faster processing, computer programs have largely been re-written to take advantage of multiple processors.

Most graphics intensive programs like Photoshop have been optimized for multiple/multi-core processors. On the other hand, some video applications, QuickTime, for instance, cannot be optimized as well for multiple processing.

RAM (Random Access Memory)

RAM (Random Access Memory) is one of the places a computer stores data. A unique feature of RAM is that this storage is very temporary. It is often referred to as volatile memory because it disappears when it is no longer needed or when the computer is shut down. Also unique is that the data is stored randomly, unlike disk, optical disc or tape storage where the data is stored at an exact physical location and requires a reading head to go to that physical location to either write or read the data.

This feature makes RAM memory many times faster than disk, optical, or tape media. In the early days of computing, RAM was small in capacity and very expensive. RAM is now one of the cheaper computer components, and now with CPU's 64-bit processing, the amount of RAM that computers can use has become very large. For instance, 32-bit processors can support 4 Gigs of RAM, while 64-bit processors can support up to 16.8 million terabytes of RAM. However, image editing applications need to be written to support 64-bit computing and large amounts of RAM before there is a performance advantage.

An interesting feature of RAM is that while RAM chips have become increasingly reliable, there is an additional advantage to have ECC (error correction code) ram to avoid data corruption. Note that desktop computers support ECC ram, while laptop computers currently do not. What happens when you do not have enough RAM installed in your computer for your processing tasks? The operating system will begin to use hard disk space instead. This is something that you generally want to avoid since this slows processing down considerably.

Scratch Disk

Scratch Disk refers to hard drive space used by an application, such as Photoshop, to temporarily store data (often in the form of history states) that won't fit into RAM. Scratch disk configuration used to be far more important in the past when RAM was expensive and limited in size. Now that applications and Operating Systems are gradually becoming 64-bit capable, it is much more likely that increasing RAM will speed up Photoshop more than exotic RAID 0 scratch disk setups (and easier to maintain).

Some tests show that larger drives, such as the new one TB drives, are actually faster than spreading the Photoshop scratch disk allocation over several smaller drives. This is due to the fact these very large drives are essentially large RAID 0 disks featuring high data density spread over multiple platters.

Graphics card

Graphics cards, also referred to as video cards or the GPU (graphics processing unit), are becoming increasingly important components of the image processing computer. GPU's have highly parallel processing capability which makes them more efficient at executing the complex algorithms used for raw file processing.

For this reason, programs such as Adobe Lightroom and Apple's Aperture depend on powerful GPU support. In general, computers that support separate upgradable video cards will be more capable with these types of applications than lower end computers that have the video card built in to the motherboard.

Configuring the workstation