My r530 installed with esxi 6.0, havent use for production for almost 1 week due to unexpected shutdown. It will shut itself after 3-5 hours. Reinstalled os (esxi 6.0) also same. OS are installed in ISDM disk (sd card). Logged call to Dell says hardware optimum. Still have warranty. I dont know what else to do. Is it the time come to change to other brand?