I ran some DMV queries to get a server's health and came across some questions..
* The signal waits query gave almost 20% for %signal (cpu) waits
* The CPU history says that SQL Server uses 1 to 0% of CPU but other processes use 10 to 30%
* The top waits are PREEMPTIVE_OS_AUTHENTICATIONOPS, ASYNC_NETWORK_IO and PREEMPTIVE_OS_LOOKUPACCOUNTSID (I had LATCH and CXPACKET but creating an index made them disappear)
Who can I determine what's causing the signal cpu waits and what type of waits are PREEMPTIVE_%?!
If you need to work better, try working less...