This is the place to show speed improvements of El Capitan over previous OSX like Yosemite using the same hardware on both operating systems. For example: My system: iMac 5K i7 4GHZ 8GB ram m295x 3TB Fusion drive Benchmark type: SunSpider 1.02 Comparing: El Capitan and Yosemite Link: Please post benchmark improvements from different macs. 8/3/2015 El-Capitan Public Beta 3 update: Just did another Benchmark "LuxMark 3.0" on El-Capitan Public Beta 3. If anyone has the same specs iMac 5k and can do the benchmark on Yosemite it can be cool. Here is a link: http://www.luxrender.net/release/luxmark/v3.0/luxmark-macos64-v3.0.zip Btw, during the Benchmark i had 2 browsers, 4 windows and 32 tabs open in the background including few apps and i have only 8GB ram installed... Hope it didn't lower the results... Enjoy!