Every computer needs RAM (Random Access Memory). Earlier, productivity applications, like Microsoft Office required very little memory, though a decent amount. Multimedia editing applications, such as Adobe photoshop also require a lot of data space. And the most power-hungry software are the graphic-intensive video games, such as Half-Life. More RAM also allows multi-tasking, which means running several programs at the same time. The more memory you have, the more smoothly your programs will run. The query of how much RAM you need is dependent on the kind of user you are. Types of Computer Users Roughly, we can categorize computer users into 5 categories. Casual: These users just browse the Internet using Internet Explorer or Mozilla Firefox. They check their e-mails using Microsoft Outlook and listen to music using Winamp. Such casual users need around 1 GB (gigabyte). Frequent: These users use word processing applications, such as Microsoft Word, Microsoft Excel, etc. They edit photos using Microsoft Picture Manager. They like playing online games, which use Adobe Flash and watching videos using QuickTime or Windows Media Player. Such frequent users need about 1 GB to 2 GB. Power: These users use photo editing software, such as Adobe Photoshop. They also use video editing software, such as Adobe Premiere. They like to play non-graphics-intensive games, such as World of Warcraft. Such users need about 2 GB to 4GB. Professional: These users play graphics-intensive games, such as Need for Speed. They use multimedia editing applications, such as Apple Final Cut Pro. They also like watching high-definition videos on Blu-ray discs. They need to use 3D modeling programs such as 3ds Max. Such professional users need about 4GB to 8GB. Extreme: When you are running heavy applications, like 3D modeling, image and video processing, etc., you might need more than 8GB memory, which might possibly extend until 16GB. Also, if you use resourceful tools, like VMWare Workstation, or you are a professional who needs to work on multiple operating systems simultaneously, you might need more than 12GB memory. Operating System Factor Different operating systems need different amounts of RAM. The 64-bit version of Windows Vista needs at least 2 GB. The 32-bit version of Windows Vista needs at least 1 GB. Windows XP and Mac OS X need only 512 MB. Older versions such as Windows 95 or 98 can do with even lesser memory. A free operating system such as Linux needs very little memory space. The Programs You Use The amount of memory you need also depends on the kind of software you are using. The PDF viewer Adobe Acrobat needs 64 MB. The Macromedia Studio MX web content creator needs 256 MB. The video post-production software Adobe After Effects needs 128 MB. If you want to burn CDs using Nero Express, you need 1 GB. Firewall and anti-virus software often run simultaneously in the background, so it is better to have more RAM to help your computer run faster. You may be instant messaging using Yahoo Instant Messenger, and video-conferencing using Skype, so you will need more memory for that. CAD (computer-aided design) software, such as AutoCAD, made by Autodesk, needs a lot of data space. A first-person shooter game such as Doom needs at least 512 MB. If you are running your computer as a server, such as a HTTP or a FTP server, you will also need more memory. For example, if you are running the MySQL database on your computer, you will need a large amount. Data compression using WinRAR and video encoding such as a DivX encoder needs a lot of memory. The more RAM you have, the easier multi-threading is for your computer. You should also check for the compatibility factor so that you don't have any problems while upgrading. Another factor to consider is how much video memory you need in your video card. Now that you know much RAM you might require, buy the chips and install them in your computer according to your needs.