Desktop computers not only have the upper hand when it comes to maintenance and upgradeability, but also when it comes to performance and capacity. While desktop PCs can easily and rather cheaply be beefed up to a terabyte or more of hard disk space, 500 GB is the current upper limit for notebooks. Expanding hard disk space is of course possible with the use of external hard drives that are connected by USB, Firewire, or, depending on the notebook model, eSATA. This limits mobility, however, and also drains the battery more quickly. Furthermore, notebook hard drives use the 2.5″ form factor, and are markedly slower than 3.5″ desktop computer hard drives. For an overview of speeds and capacities of current hard drives, our article Comparison of fast notebook hard drives , The terabyte battle: Barracuda 7200.11 vs. Caviar GP and DeskStar 7K1000 and Spinpoint F1 with 1 TB: Samsung sets the tempo.
As with hard drives, if you compare processor capability, you realize that notebook CPUs are also inferior to desktop processors. This does not have as noticeable an impact on daily work as the differences in hard drive performance, though. While mobile processors tend to be adequate, a slow notebook hard drive can severely restrict productivity. This may result in long waits while starting Windows, copying large files, or using applications that require that a lot of RAM be placed in the swap file on the hard disk.
As is the case for processors, the actual differences in performance between notebook RAM and desktop RAM is minimal. While clock rates for notebook RAM are usually 667 MHz, desktop units connected to DDR3 memory modules can attain clock rates of up to 1600 MHz. Despite this, most desktop computers still use DDR2 memory modules for cost reasons, which have a clock rate of 800 MHz. The difference between DDR2-667 and DDR2-800 modules in everyday office tasks on the computer is negligible, and can be disregarded by average users. (Also see: DDR3 luxury class: High speed, low impact) You have to realize, however, that most desktop systems will allow for more than 4 GB of RAM, whereas 4 GB of RAM is limit for today’s notebooks: there is simply no space for more.
Optical drives perform at a high level in both desktop computers and notebooks. Though price differences between slimline drives for notebooks and drives in the 5.25″ format used to be considerable, the prices today are basically equal: the difference is only about $23.19. This is principally due to the fact that notebook sales in recent years have risen considerably, which resulted in increased production of slimline drives, and consequently, lower prices. In terms of the performance capability of these two kinds of drives, we have to conclude that the performance data is not as dramatically different as in previous years. For end users, there is virtually no difference if a slimline drive or one in the 5.25″ format is used.