X9, X10 2011-socket server board, and qualified E5-Xeon CPU. There are many really good priced CPUs on the web how do I know it is qualified.
This can be confusing, but there are OEM CPUs that are built specifically for certain vendors and may be modified or need modification of the motherboard to use these CPUs. The giveaway is if you Google the model number of the CPU. For example, E5-2699v4 will have a link to Intel's product specification page (URL starts with ark.intel). An OEM version such as E5-2696v4 will not have a product page. Of course stay within the TPD of the motherboard spec, and memory as well.