The main reason why a graphics card won't "do" for a motherboard is due to the Pcie type difference. This does not mean that your card won't fit in the slot, it will rather not be able to fully provide you with its maximum capabilities. To expand things, all pc hardware are backwards compatible (in terms of performance). If your motherboard has a Pcie 1.0 bandwidth type and your graphics card has a Pcie 3.0, then your graphics will only work with the speeds that your motherboard is able to support (i.e the card will basically downgrade to Pcie 1.0 speeds). If on the other hand your motherboard can support up to Pcie 3.0 speeds and your card can perform 100% at Pcie 1.0 speeds, then it will be able to run at its maximum capabilities, because the motherboard allows it to do so.
Regarding your motherboard I would like you to provide us with some more details in order to filter out some possible gpu upgrades.