Photoshop requires a monitor set for at least 1024 x 768 pixels at a bit depth of at least 16 bits per pixel (thousands of colors). Fortunately, most new desktop and laptop computers being sold today are capable of well beyond the minimum requirements for Photoshop. Photoshop displays best if you set your monitor to 32 bits per pixel at the highest monitor resolution that's comfortable for you. You don't want to run at the minimum specifications anyway1024 x 768 doesn't leave much room for palettes, and 16 bits per pixel doesn't represent color quite as precisely as the 24 bits per pixel (millions of colors) that color professionals use as a standard.
Another great efficiency booster is to attach a second monitor to your computer, so that you can spread out your work area and prevent palettes from covering the image window. If you want to run multiple monitors, make sure your computer or your video card has an additional monitor port available, and is capable of driving at least one of those monitors at the resolution and bit depth Photoshop needs. I talk about multiple monitors in more detail in the section "Optimizing for Multiple Monitors" in Chapter 2.
In most computers, monitors are driven by the video card that came with the computer, and that's usually fine. You can buy a different or newer video card if you want to:
Video cards work in computers that have an expansion card slot. At this time, most video cards for desktop computers are PCI compatible; those for laptops fit in a laptop's PC card slot. If your computer doesn't have a card slot, there are some video solutions that connect to the USB or FireWire port, but they are not usually suitable for Photoshop use.
It isn't hard to shop for a video card to use with Photoshop. Thanks to gamers, who have continually demanded better 3D video performance, most video cards are capable of displaying millions of colors on large monitors and work great for Photoshop. When you shop for a video card, don't be concerned about 3D performance at all (unless you're a gamer). Pay more attention to the number and type of video output connectors, and make sure the card can drive your best monitor at the highest resolution it supports.