Quick set up. Genuine i7 6700. Installed with Windows 10 Pro. No optical drive but there is a slot for one. 2 slots for internal hard drives besides the 1TB OS drive. Currently working on installing the extra drives. Stay tuned for more. Completed install of 2 more drives successfully. There is 2 extra sata data "cables" inside but you will need 2 sata power cables for which there are slots for. Installed a 1.92TB 2.5" SSD with an adapter tray in the bottom slot and a 4TB 3.5" HDD in the top slot, you will need screws. All in and working well. Remember you will need to format any new hard drive so your computer will see it. UPDATE = Operating System has failed, no longer boots = Bad generic SSD. Will be contacting seller and most likely returning unless they send a new hard drive. These things happen, still like the unit. Received a Full Refund from seller, purchased again from a different vendor. The second unit sent is a EliteDesk 800 G2 with the same features and has been operating perfectly since boot up. As of 5/18/2024