i7 in a HP Prodesk 400 G1 - A cheap but superfast machine! - YouTube
HP Prodesk 400 G1 MT Casing Fan 4-Pin 92*92*25mm DS09225R12H (Refurbished)
Specs HP ProDesk 400 G1 MT i3-4130 Micro Tower Intel® Core™ i3 4 GB DDR3-SDRAM 500 GB HDD Windows 7 Professional PC Black PCs/Workstations (D5T94EA#ABH-LB)
Desktop Motherboard For HP ProDesk 400 G3 MT MS 7957 DDR4 1151 793305 002 793739 001 System Board Fully Tested| | - AliExpress
HP 718775-001 ProDesk 400 G1 MT motherboard 718413-001 | eBay
Specs HP ProDesk 400 G1 MT i3-4130 Micro Tower Intel® Core™ i3 4 GB DDR3-SDRAM 500 GB HDD Windows 7 Professional PC Black PCs/Workstations (G9E50EA+U6578A)