If you’re interested, the Dell T1650 is currently supported by Libreboot. I use it for everything; it has a Xeon E3 1275 V2, 32GB DDR3L ECC RAM, NVIDIA 2080 SUPER, 2x4TB HDD (RAID 1), 1TB NVMe M.2 (PCIe x4 adapter needed), and a 700W PSU (EVGA 700BR). It handles all my games, and I use Proxmox VE as my host, allowing me to create virtual machines where I can passthrough my GPU and use anything proprietary in the VM. Even the GPU drivers can be passed through (no need to install on the host), so essentially, I’m running 100% free software on my host.
Obviously, nothing can be 100% FOSS in the hardware (proprietary ECs, proprietary CPU microcode, proprietary storage firmware, etc.), BUT you can free the BIOS. There is currently a blob needed for the PCIe x16 slot, but it can be reverse-engineered in the future – not sure if there is anything else; I’ll have to ask. There is one board coming soon that I know can be made blobless in the BIOS, and that is the Dell Optiplex 9020 MT. It’s a Haswell board capable of using an i7 4790K with AVX2 instructions. I’m actually the first person to use this board, as I’m the one who made the port along with some help from the Libreboot team. The board is currently in its testing phase still, but soon in the next couple weeks we will make it freely availble.
This is super cheap hardware; you can find the whole PC on eBay for like $50-$60, or you can just buy the motherboard for like $15-$25. I bought only the motherboard because I’m using it in my gaming computer case. Also, you don’t even need any fancy flashing equipment, all you need is a insulated screwdriver to short one of the SERVICE_MODE pins on the motherboard to unlock the BIOS chip, which then allows you to flash Libreboot through your OS. Libreboot is more secure than any non-free BIOS/UEFI. At least with Libreboot, you can have transparency, and you get new updates with better features coming out.
For example, Libreboot supported Argon2 encryption in GRUB for fully encrypting your storage drive. This allows you to encrypt the /boot partition and fully encrypt your disk with ease when installing a fresh operating system. Also, you can run Windows on the host with Libreboot, it is supported but not officially. I highly recommend Libreboot, as you can tell.
I own a Dell T1650 and Dell Optiplex 9020, and yes you are correct about them making everything proprietary, but the motherboard can still be used as long as you have the adapters for it. You will need to DIY, or buy a custom cable from a vendor that makes them for the motherboard. I use a Dell Optiplex 9020 MT motherboard in my NZXT case, I use a EVGA 700BR, a custom 24 pin to 8 pin connector, and a molex to fan adapter cable for my other fans, and everything works great! Also, I added Libreboot support for it as well :D
CPU FAN: https://www.amazon.com/Cooler-Master-i70-CPU-RR-I70-20PK-R1/dp/B07QNN9MW3/ref=pd_aw_ci_mcx_mh_mcx_views_0?pd_rd_w=uGY4W&content-id=amzn1.sym.0e5c7f8b-153f-45ea-a1fd-9585fc3a0cd5%3Aamzn1.symc.2b06b7e8-a86c-4e6e-b02c-90d58278f4f1&pf_rd_p=0e5c7f8b-153f-45ea-a1fd-9585fc3a0cd5&pf_rd_r=NJ3TZ775JESQ13BRMSND&pd_rd_wg=031k7&pd_rd_r=981f2986-2fe4-4291-a6c6-8daa32270b4e&pd_rd_i=B07QNN9MW3
CPU FAN ADAPTER CABLE: https://www.amazon.com/CRJ-5-Pin-Female-Adapter-Motherboards/dp/B0871P9X72/ref=mp_s_a_1_5?crid=19CH0DE3GUFGG&keywords=dell+optiplex+9020+fan+adapter&qid=1694594053&sprefix=dell+optiplex+9020+c+fan+adapter%2Caps%2C683&sr=8-5
POWER SWITCH CABLE: https://www.amazon.com/Warmstor-3-Pack-Desktop-Button-Computer/dp/B072FMVZJZ/ref=mp_s_a_1_3?crid=2KW0OE1E7QEFW&keywords=power+switch+cable+for+pc&qid=1707797019&sprefix=power+switch+cable+%2Caps%2C111&sr=8-3
28 PIN TO 8 PIN ADAPTER: https://www.moddiy.com/products/Dell-OptiPlex-9020-PSU-Main-Power-24-Pin-to-8-Pin-Adapter-Cable-30cm.html
MOLEX TO CASE FAN ADAPTER: https://www.amazon.com/Molex-Case-Sleeved-Adapter-Cable/dp/B08393S29W/ref=mp_s_a_1_4?crid=YC96W76081OT&keywords=molex+to+fan+adapter&qid=1707797145&sprefix=molex+to+fan+%2Caps%2C91&sr=8-4