I have no answers for you but find this project fascinating and would love it if you documented (photo/video) some of this journey 😀

I'd be interested as well, since the assisted suicide of VMWare by Broadcom I have a desire to rip out ESXi from my home lab server and replace with something else.

Proxmox seems like the best all in one.

Bought some parts so we'll see how this goes. If it works I'll have to decide if I buy a case per GPU or replace the GPU. For longevity thinking a case per.

If I have the 7900xtx as a egpu for 10+, 980ti internal for XP, Vista and 3060 for 7-8 on this 5950x then that's pretty good.
If I wanted I could do another case for 1080ti for Vista (waste of money for another case.....) or a 3080 case and remove the 3060 and replace it was a Geforce FX 5200 for <= 2000 but I'd need to see if I have a PCIe slot for an Audigy otherwise I'll just have an X-FI for XP and onboard audio for everything else.

I don't want my i7 6700k to go to waste so I'm fine with it being a <= 2000 machine with XP+ as backup with a 780GTX for now.

If there is any interest then I'll post parts and pics once I have it working.

Tested 980ti and X-Fi in 5950x machine which work well.
Took the 3060 out of the 5950x machine for the oculink card when I get it.
Replaced the 980ti in the i7 machine with a 3080. This will be swapped out with the 780GTX when/if I make the 3080 a egpu depending on how well the 7900xtx egpu goes.

Current machines:

PROXMOX TEST 2000/XP/Vista/7/8/10/11/Linux

CPU: Ryzen 9 5950x
CPU Cooler: Corsair iCUE H150i w/ 3x Noctua NF-A12x25 PWM chromax
Motherboard: MSI Meg X570 Unify
NIC: Intel Ethernet Converged Network Adapter X550-T2 (10GB)
Memory: G.Skill 32GB DDR4 PC4-28800 3600MHz Ripjaws V for Intel CL16 (16-19-19-39) Dual Channel kit (2x16GB)
GPU: 8800GT 512MB (2000 Vanilla)
EGPU: Zotac Geforce GTX 980 Ti 6GB AMP! Extreme GDDR5 ZT-90507-10B PCIe (Windows XP+)
EGPU: GIGABYTE Gaming OC GeForce RTX 3080 10GB GDDR6X PCI Express 4.0 ATX Video Card GV-N3080GAMING OC-10GD (rev. 2.0) (7+)
Video card: EGPV-1101-C1 M.2 (Proxmox Console)
Audio: Realtek® ALC1220 (Vista+)
Audio: Sound Blaster X-Fi Titanium (XP)
Audio: Creative Sound Blaster Audigy PCIe RX 7.1 (9x/2000)
Monitor 1: Acer XB271HU 27" 2560x1440 "Acer Predator XB1"
DVD: Blu-ray LG WH16NS60
SSD: Seagate FireCuda 530 1TB
SSD: Seagate FireCuda 530 4TB
PSU: CORSAIR RMx Series, RM1000x, 1000 Watt, 80+ Gold Certified, Fully Modular Power Supply
Case: Corsair 600C Black ATX Full Tower Computer Case w/ 3x Noctua NF-A14 PWM chromax

EGPU x2 (one for 980 TI and another for 3080)
Cable: ONE XPLAYER OCuLink Cable for OneXGPU eGPU, SFF8611, 3.3ft Long, PCIe 4.0 x4
Adapter: NFHK 4X Oculink SFF-8612 SFF-8611 to PCIE PCI-Express 16x Adapter with ATX 24pin
Case: Fractal Design Ridge Black - PCIe 4.0 Riser Card Included - 2X 140mm PWM Aspect Fans Included - Type C USB - m-ITX
PSU: Corsair SF Series, SF750, 750 Watt, SFX, 80+ Platinum Certified, Fully Modular Power Supply (CP-9020186-NA)
Occulink card: PCIe x4 Gen4 with ReDriver to OCulink 4i Host Bus Adapter

PROXMOX Test DOS\9x (VESA)/NT4 (VESA)/2000 (XP+ Backup)

Processor: Intel Core i7 6700k
CPU Cooler: Noctua NH-U9S w/2 Noctua A9 92mm fans
Motherboard: ASUS PRIME Z270-A
Memory: Patriot Viper 4 32GB (4 x 8GB)
NIC: Intel X540-T1 10GB
SSD: Seagate Firecuda 530 1TB (Proxmox)
SSD: Seagate Firecuda 530 2TB (Proxmox VMs)
PSU: Corsair RM850x
Audio: Creative Sound Blaster Audigy PCIe RX 7.1 (9x/2000/XP)
Monitor: Dell Ultrasharp U2410F 24" 1920x1200
GPU : Geforce GTX 780 (2000 BWC/XP+)
GPU: Geforce FX 5200 128mb (9x-NT) (2k-xp for games that need it)
Case: CoolerMaster ATC-110 w/ 4x Noctua NF-A8 PWM fans
Amebay 5.25 Inch Front Panel USB Hub 2port 3.0, USB 2.0 for Computer Case
DVD: Blu-ray LG UH12LS28

Got the egpu built, just waiting on the oculink card. If it works then pics if it doesn't then mabye pics. heh.

Got the final part today but found out during testing that the 7900 xtx is incompatible so swapped it for a 3080. Verified that passthru works via proxmox, installed the drivers, verified pcie 4.0 x4 and loaded cyberpunk. Won't be able to test more until after the weekend.

DLSS quality w/pathtracing at 1440p was 38fps which I think is pretty good but would need to check reviews. All I need is good enough for mostly testing and sometimes playing so should be good.

Did some testing today after putting the 7900 xtx back in my computer. Likely not an incompatibility issue, I choose "All Functions" for Nvidia cards to allow the card audio to work but for the 7900 xtx you can't choose this option. You have to add the audio as a seperate device. sigh.

At least this means I can make this card external now and free up some slots.

Parts

Cable: ONE XPLAYER OCuLink Cable for OneXGPU eGPU, SFF8611, 3.3ft Long, PCIe 4.0 x4
This length is important since anything shorter may not reach. Even if there were SFF8611 external brackets for both PC cases you'd likely still want a long cable to be able to position the egpu case where you want. Make sure you get a 4i adapter, 4i cable and 4i card. 8i is a different connector.

 Adapter: NFHK 4X Oculink SFF-8612 SFF-8611 to PCIE PCI-Express 16x Adapter with ATX 24pin
This works at PCIE 4.0 x4 and also powers off when the PC powers off. That capability wouldn't work in one PCIE slot but did in another for some strange reason. If it doesn't work on your computer you'll have to yank the power cable. Card has a light to tell you when it has power.

Case: Fractal Design Ridge Black - PCIe 4.0 Riser Card Included - 2X 140mm PWM Aspect Fans Included - Type C USB - m-ITX
I removed the 2x 140mm fans and am just using the GPU fans. Currently monitoring thermals to decide if it's worth adding fans. For 4090/7900 xtx there is no room for 140mm fans but possibly for 60/80mm fans at the top. Since I have the adapter plugged directly into the riser card then the space for where one 140mm fan would be is being used by that.
Oculink cable is routed out through where the I/O backplate would be and is then routed through a PCIE slot to plug into the occulink card.

PSU: Corsair SF Series, SF750, 750 Watt, SFX, 80+ Platinum Certified, Fully Modular Power Supply (CP-9020186-NA)
Quiet PSU with short easy to work with cables.

Occulink card: PCIe x4 Gen4 with ReDriver to OCulink 4i Host Bus Adapter
Works at PCIE 4.0 x4 with a 3.3ft cable. Also has a green light to tell you when it has power.

Here are the pics.
The pics were taken with the 50cm cable which is too short.
Forgot to take a pic of the top. It isn't that interesting, possibly space for placing two 60-80mm fans zip tied.

Thing I like about using a PC case is it can be repurposed whereas a case dedicated for a EGPU cannot. So yes there is a bit of "wasted" space but not much.

That's a really smart idea using that SFF case as your GPU enclosure.

Well it wasn't my idea, spent alot of Internet searching and found a suggestion buried in a post. Most of the egpu talk is buying an already built unit that comes with a GPU or using a dock. The remaining small number are those that build their own enclosure. Those using a PC case to house a GPU seem to be very rare and those doing so to connect to a ATX PC are even rarer (instead of a laptop or mini pc). heh.

I just now received the same parts as above so I can build the second one which will house the 7900 xtx. Still waiting on another cable.
The above pics were taken before I swapped it out with a 3080.

Thought this was interesting:
https://www.anandtech.com/show/21379/pcisig-c … 50-60-get-wired

Still having issues with the 7900 xtx, replaced with the 980ti and placed the 8800GT in the 5950x machine.
This allows that machine to work with Windows 2000+ w/passthrough for audio and video.

Had to remove the SF750 in the case for the 3080 since the SF750 in my main PC (small case so no room) stopped working.
I have a Silverstone SX1000 SFX-L 1000W which might be working so even though the wattage is high just for usage with a 3080 I'm not going to buy another PSU for this egpu if I don't have to and I don't have the space for this PSU in my main PC. Have to order some cables for it though since they seem to be missing.

One thing that does give me pause is the PC I removed it from had a mobo that mysteriously had power cycling issues and eventually wouldn't power on so guess we'll see.

Oculink vs USB4. Remains to be seem what TB5 looks like.
https://www.xda-developers.com/oculink-egpu-hands-on/

Received the cables for the SX1000 and placed in the other Fractal Ridge. Not as tight as I thought it would be and the SX1000 comes with flat cables which is probably why. Verified it powers on and passthrough works.

Did some testing with a HD 4870 in Windows 2000.
It works but:
Fan noise is too loud until the driver loads, whereas the 8800GT isn't.
Same reset issue as other AMD cards where you have to power off and power on the PC after using it once. (vendor-reset doesn't work likely due to old GPU). Suspend script works sometimes but I'm not looking for sometimes works

Decided to take out the AMD HD 4870 and stick with the Nvidia 8800GT.....which is the same as it was back then so no different heh.