Original HP Envy 750 Series Intel LGA1151 Desktop Motherboard 862992-001 862992-601 IPM17-DD2. 

HP Part Number: 862992-001
Compatible Part Numbers: 862992-601 IPM17-DD2
CPU: Intel Xeon E5-2623 v3 3.00GHz SR208 Processor
Compatible Models: HP Envy 750 Series