Maxis has revealed the system requirements for Open for Business. Similar to Nightlife, this expansion pack will require a processor with a clock speed of 1000 Mhz (1 GHz) or higher (2.4 Ghz if you don't have a T&L capable graphics card). This is more than the original game, which requires 800 Mhz. Besides that, you'll also need an extra 1.5 Gb of disk space. During installation the program will probably need a little more to be free, for temporary files as well. Another change compared to the original (but not since Nightlife), is that the ATi Radeon 7000 series are no longer supported - an ATi Radeon 8500 is the bare minimum for ATi's range of graphics cards. For more detials see the official System Requirements page and our knowledge base article.