The Google Chrome OS will be super lightweight that runs as fast as what the Google Chrome browser does. In fact the Chrome OS is basically the web as an OS, developers can develop applications for it just as what they would develop on the web, pretty similar to the approach that WebOS for Palm Pre takes. Google says the architecture of this Chrome OS will basically be the current Chrome browser running inside “a new windowing system on top of a Linux kernel.” And some more it’ll be open-sourced like the web browser.
Google Chrome OS is able to run on both the x86 architecture chips and ARM chips, the one increasingly found in netbooks. Perhaps, there is an overlap between Android and the new Google Chrome OS. But the obvious difference is Android does not run on x86 architecture, while Chrome OS does. Link