CKEditor editing. A custom collaborative solution can be build by using the CKEditor 5 Framework components and real-time collaborative editing can be enabled by connecting to the CKEditor Cloud Services. A ready to use, drop-in component based on CKEditor 5 (Letters) offers a complete solution for real-time collaborative writing. CKEditor 4 is fully compatible with most internet browsers, including latest stable releases from Google Chrome, Firefox, Safari, Microsoft Edge, Opera and Internet Explorer 10 and 11. In mobile environments, it has close to full support in Safari (iOS6 +) and Chrome(Android) CKEditor 5 is also compatible with Google Chrome, Firefox, Safari,
Firefox and sixth-fastest browsers, respectively, on startup, 3.5 was third- and 3.6 was sixth-fastest to load nine tabs at once, 3.5 was sixth- and 3.6 was fifth-fastest on the JavaScript tests. They also concluded that Firefox 3.6 was the most efficient with memory usage followed by Firefox 3.5. In February 2012, "Tom's Hardware" performance tested Chrome 17, Firefox 10, Internet Explorer 9, Opera 11.61, and Safari 5.1.2 on Windows 7. "Tom's Hardware" summarized their tests into four categories: Performance, Efficiency, Reliability, and Conformance. In the performance category they tested HTML5, Java, JavaScript, DOM, CSS 3, Flash, Silverlight, and WebGL (WebGL 2