The difficulty is because you never know what BIOS is installed on a motherboard, before you purchase is. Supposedly, as stores restock their supply of a motherboard, the manufacturer ships out their boards with the latest BIOS installed, but there is always a chance that you could get a motherboard that's been sitting on a shelf for too long and does not have an updated BIOS.
I believe some manufacturers do put a BIOS version sticker on the outside of the box the motherboard ships in, so you may be able to determine it that way, but aside from that, the only way is to try it and see. If it doesn't work, you would either have to get a low-end, supported processor so you can update the BIOS or take it to a shop and have them update the BIOS for you.
-Wolf sends