Generally for most people any new driver set for 4-5 months will set the correct multiscreen clocks until you overclock AT ALL, usually after hitting the unlock in the CCC. The latest set on a fresh install of windows 7(ssd died, for a second time ) set the 400/900 clocks normally, as soon as I tried overclocking no matter how many restarts after overclocking it always defaults back to the uber low clocks which is a shame, but completely unavoidable on this generation from either company.
Theres several options, go into CCC, top right drop down menu, go to profiles, click overdrive each screen set a name and save a new profile, go to the profile) app data>local>ati>ace>profiles, and change the lowest core clock to 400 and change all the memory settings to 1000(or higher for 3d if you want).
That should for the majority of situations force higher 2d idling clock speeds, there is NO way around this, and its not worth blaming ATi like a bunch of Nvidia guy shave for 6 months, Fermi has the problem and has it worse as they seem to be running full 3d speeds and voltage at idle with more than one screen attached.
Its a timing issue, likely, because both companies have it, caused by some fundamental incompatibility with dropping gddr5 clock speeds and Microsoft power schemes. It would also appear the grey screen of death issue came up after MS made an update to the way it changes power settings.
You other options are, using MSI afterburner to set a 2d/3d speed for you, this will probably allow you to overclock past default clock limits while maintaining "powerplay" at a high enough speed to prevent problems.
You can also use gpu clock tool to set your default 3d speed, using gpu clock tool to overclock, to ANY speed, stops powerplay working at all, not sure why, but it will fix the flickering, again if you clock high enough.
On first release the profiles weren't forcibly setting the higher 2d speeds you can set so I used gpu clock tool for the first month or two, then MSI afterburner could overclock/volt any 5850/5870 so I started using that.
Right now, to get the lowest stable voltage/idle speeds I use the CCC profile to set 400/1000 0.95v for idle, with the highest CCC clocks which you can also put in the profile, as the 3d speed(so what is it 775/1000mhz and leave the 3d voltage as it is).
I think use MSI afterburner to use higher than CCC allowed overclocking/voltage when I want a bit more power and speed. Save your highest overclocks as one profile and I keep a "default clock speeds" profile to enable after gaming, which allows the CCC to take over idle clock speeds.
Odd but after you go outside the CCC default clocks with any 3rd party overclocking tool, powerplay and 2d speeds stop, but resetting the clock speeds below the limits will re-enable powerplay for idle.
You can have MSI afterburner control 2d clocks for you, but I find that less effective, less stable and you can't go as low on voltage for idle.
Keep in mind that my experience across 2900xt, 8800gtx, 8800gt, 9800gt, 3870x2, 4870x2, 4890 and a 5850 all suggests that MOST in game crashing and instability comes from having your card constantly switch between 2d/3d clock speeds IN A GAME. Because they'll switch during some cutscenes, some menu's, some when they detect a pitiful load.
The method I highlighted, use CCC to set higher idle speeds, and MSI to flick between a SINGLE overclocked speed that won't change to any lower speeds under any circumstances, and a default speed profile that will re-engage powerplay gives you the best stability, overclocking stability, game stability and idle power usage.
EDIT:- I know its a pain that AMD don't list fixes on their website, and I complain that few if any companies just give you a dedicated pages of the latest fixes and idea's, Intel, AMD, AMD(but specifically ATi) Nvidia, no one, mobo makers don't list a common set of updates/fixes/workarounds either.
But you won't get a bios update from AMD, unless its a completely flawed product that doesn't work the risk of loads of people flashing bios's will result in people who don't need the fix thinking their card will be better, and a lot of them will smeg it up.
Sapphire probably don't officially maintain the warranty if you flash the bios, though most people wouldn't have trouble after a successful flash if the card died of something else. But the main thing is, theres just no need, it can all be fixed in software for 99.9% of people with ease. But yeah, AMD should say this somewhere really obviously on their website, as should everyone else with their own little fixes for their own products.