As with any piece of software, Visual Studio uses resources on your computer. The use of those resources can be directly proportional to the complexity.
The recommended configuration for Visual Studio is a 1.6 GHz processor, 1 2 GB of RAM, 3 GB available hard drive space, 5400 RPM drive, and so on. While this setup will likely allow Visual Studio to run, it's not going to be running as fast as it can.
To start off, the lower the amount of RAM the greater the possibility that Windows will start swapping memory in and out to disk. This is really expensive. It's probably the slowest thing that can happen without accessing the network. It's recommended that you put as much RAM on the computer as you possibly can. For 32-bit processors, this limit is 4 GB. This effectively gives you 2 GB of RAM that can be physically committed per application. If you have a 32-bit processor, it's highly recommended to have 4 GB of...