What BIOS are you running and what's the full model name and revision of your board? It looks like all of the 990FXA-UDX boards have patched BIOSes, F6 or higher.
If the latest one for your board doesn't work (or F6, as AMD recommends), you should do a support ticket. Just do what I did and say you have X board, revision Y, with Z BIOS, and you're having the Steam crash (add a link to the AMD issue page that describes it so they know it's a specific issue). Tell them what CPU you're using. Ask if they're going to issue a patched BIOS for your board. Don't be discouraged if their first response is kind of Engrish and not really helpful, just make it clear that you're looking for a patched BIOS.
The BIOS they sent me is specific to the 890fxa-ud5, and I'm assuming specifically the 3.1 revision of the board. I don't think you'd want to flash that... Besides, I think the 9 series BIOSes are numbered differently.
I would assume that they're either working on something or they can send you a patched one. The 990fx boards should have as much or more support than the old 8-series boards.
I've since played some Shogun and finished Deus Ex HR, so 890fx FEd is definitely pretty stable. I'm not sure why they haven't added it to the board's download page, unless it's still going through testing.