I know the following:
1. PCIE 3.0 cards are backwards compatible with PCIE 2.0 slots (not sure 1.1)
2. plugging into a lower PCIE slot will bottle neck GPU, but not by too much. (at least in the case of PCIE3 card into PCIE2).
Questions are:
1. What will happen if I try to plug in a RX 6000 or RTX 3000 series card into a PCIE 2.0 slot? Will it work? And if so, how much will the PCIE 2.0 slot limit the speed by?
2. I currently have an RX 590 in the slot. Let's say for example RX 6700 is 3 times RX 590 when plugged into a PCIE 3.0 slot. And let's say my PCIE 2.0 slot is bottle necking my RX 590 a bit, maybe by 15%. When I then plug in my RX 6700 into the PCIE 2.0 slot, will the card also be bottle necked by the same proportion, having it's performance cut down by 15%, and still be 3x as fast as my bottle necked RX 590? Or will the dif between PCIE 4 and PCIE 2 be so great that my RX 6700 will effectively be only 1.5x my RX 590? Or maybe even the same as my RX 590, if that's possible?
I'm sure there is math involving bus speed and teraflops and whatever to calculate this, but I'm nubcake.