Buildapc

Don't buy them new. They are like 500% markup from consumer cards for not much performance.

Try to get 2 year old ones, from businesses that sell them at the end of warranty (or liquidation sales). You'll probably have to buy the whole tower with it but you can usually flip it.

That being said, have you tried passing your 3090 to a VM and the VM has the new drivers for it? You would get poor graphical output performance but compute is compute.

Also: quattro cards usually only have displayport, or even mDP. Be mindful of any adapters you may need.

It took some trickery (that I don’t remember) but I was able to get my 3080 laptop to support the ancient unsupported Nvidia GPU with both running their correct drivers. Have you tried fiddling around with updating and rolling back drivers in device manager?

And unless you need the certified drivers (which it sounds like you might not even be able to use) or the extra floating point performance then quadros are a waste of money.

Also from what I can tell modern GeForce and quadros can only drive 4 displays at a time. My ATI 5870 from 2010 can do 6 displays, but for whatever reason they decided that was too many and went back.