Precision T7910 compatible newer gen GPU matrix

I believe that the PCIE slots in the T7910 are Gen 3 (two(2) x16 slots) and Gen 2.  

Thanks. Is anyone aware of any PCIe expansion card that allows for adding PCIe gen4 slots into this type of model?

I don't think it works that way.  You'd be plugging a device into a Gen 3 slot (which has a fixed communcation bandwidth) in the mobo and expecting it to increase the intrinsic bandwidth of the motherboard.  Not gonna happen.  On the other hand, Gen 4 devices should be backwards compatible so you'd get a working device and Gen 3 comm bandwidth. 

The point is, if you want true Gen 4 PCIE communications bandwidth, you need a mobo with Gen 4 PCIE slots.  Not sure that I've seen many of these.  The later Dell workstations (e.g. T7920) still have Gen 3.  Anybody know of any dual CPU mobo with Gen 4 slots?  Maybe I'm misinterpreting this.

Yes. I believe the challenge is, I dont think there is a motherboard that has that slot for a T7910. It sounds like the only option  is to try external eGPU

Quick question: what are you trying to do?  Is this an app where you are using the card as a numeric processor?  If so, if your compute task consista of a lot of smaller calcs (that is if the compute task doesn't need to interact with RAM a lot) then the card might be able to 1) get the program and a small starting data set over the PCI3, 2) do the calcs internally with no PCIE bandwidth needed, and 3) transfer a parsimonious set of calcuation results back to RAM.  If you are simulating nuclear warhead detonation, or the worlds weather system, where you need a lot of I/O between RAM and CPU then... you may need to find a bigger computer.  
I have a friend running dual EPYCs and four 3090s in a case with 2TB of RAM.  He's simulating the atoms in DNA to assess likelihood of a double strand break.  He got a more recent computer than a T7910 because, in part, the memory speed limits on our computer are pretty low.  To that point, if your task requires a graphics card that communicates at 64Gb/s (PCIe4) you may want to rethink using an eight year old platform limted to DDR4 2400 memory. You'll be memory speed bound.  My two cents.  
What are you using this for?

If you're still interested in options, I have an RX 6700 XT 12Gb running just fine in my T7910. It required some tinkering to get the power connectors fixed, I spent less than € 30,00 on a couple of adapters. This card is great for CAD tasks, the pcie 3.0 motherboard doesn't hinder performance. 

Hi, thanks for the reply. If you wouldn't mind sharing what parts you had to get to make it work.