Greetings:
I just resurrected my black Origen S21T case two days ago. It has been dormant over five years. In the past, I have Windows 7 and 8 on it, then discarded the mobo, then installed Asus P6 mobo.
As we speak, I am setting it up. The case is small, you will look for Zotax rtx 2070 mini, gtx 1070 mini(old) stock.
I think there are 2 versions of the RTX 2070 card.
I am making plans to pick up one of the RTXs. It is on my radar. It takes up 2 slots, about 8.8 inches long. It will fit the Origen S21T case.
I plan on using this build for Ubuntu/Android.. dual boot.(hopefully JRiver for Android will have Video features soon)
If you want to use it for Linux, there is a Linux driver for touch screen on the Origen website.
If you can not find it, let me know. I will file attach to you via PM.
Origen S21T is a very difficult case to build on, because of its small size. I have torn apart mine and reassembled twice.
Cable management is very important.
I fitted mine with Corsair memory sticks, on top of it is a Corsair fan to cool down the memory.
I have the rear fans in push and pull configuration.
I plan on putting the VGA fan metal schroud on top of the Nvidia card to help suck out the heat from the case.
I hope this info helps.
George