So currently I have a HD 5870 and a HD 3850 in my system. Im using the 5870 for my primary monitor and the 3850 for secondary monitors. I have drivers for both cards installed and everything is working alright. 

Then, for w.e reason when I try to update the drivers everything breaks. For example, I tried updating to 13.1 today and after the driver finished installing I was greeted witha  blue screen and when I rebooted my secondary monitors didnt work and the resolustion was messed up on my primary monitor. The only way to fix this is by rolling back the drivers for the 5870, at which point I reboot and everything is back to normal. 

For some reason my current CCC version is still 13.1 even though I rolled back. 

Sorry for wall of text, tl;dr:

So my question is, is there a trick to doing drivers when you have 2 different cards in your system? Or should I just keep updating and then rolling back when I want to update the drivers? 

AMD moved support for all cards before the 5000 series to legacy drivers.  What that means is that all mainline driver versions past 12.4 cannot support both your 3850 and 5870.

Windows XP, 7, and 8 do support multiple different graphics drivers at once, but I don't know if the legacy AMD drivers are sufficiently distinguished to be installed side-by-side with the mainline drivers.  You could always download 12.6 legacy for the 3850 and 13.1 mainline for the 5870, and see if you can install them both.  Probably can't, but it's worth trying.

Otherwise, you're stuck with 12.4 unless you replace the 3850 with either a post-4000 AMD card, or another brand of card entirely.

You cannot have 12.x and 13.x at the same time, as you cannot have multiple files with the same filename in the same directory. It's that simple.

The blue screen happened because 13.1 overwrote some 12.x files, and therefore it became incompatible with the 3850.

Solution: Use 12.x only or replace the 3850.

Suggestion: The 5870 should be able to handle all 3 monitors by itself. You don't need the 3850 at all.

CPU: AMD Phenom II X4 810 @ 3250MHz | RAM: Kingmax 2x2GB DDR2 800 @ 833MHz| MoBo: MSI K9A2 CF v1.0 (BIOS: 1.D)| GPU: Asus HD 6850 1024MB (DirectCu) @ 850/1100MHz | Display: Chili Green Vision L24FHD | PSU: PC Power & Cooling Silencer 750 Quad | OS: MS Windows 95 x64 Edition

CPU: Pentium 4 Northwood S478 @ 3200MHz | RAM: 1,5GB DDR 400| MoBo: Gigabyte GA-8S661FXMP-RZ | GPU: Abit Geforce Ti 4200 | Display: Dimarson 19" CRT | PSU: Noname 400W | OS: MS Windows XP Pro, Fedora 18

I have (or had) the same issue as you.  I have an HD6950 2GB for gaming and a FirePro3D V5700 for CAD.  This worked well until last fall when AMD stopped supporting the HD2xxx, HD3xxx, HD4xxx and all FirePro3D cards older than the V5800.

My temporary work around that worked a couple of months until Catalyst 12.10 was to hack the inf for the gaming version of my CAD card, which is the HD4650 (RV730), and install the core driver for 12.6 for the V5700 (using the driver for the HD4650 with the INF modified to make the V5700 be detected as an HD4650).  To my surprise this not only allowed both cards to work side by side, but the HD4650 driver allowed the advanced CAD features to work, enabling enhanced graphics features with Solid Works.  The Catalyst Control Center even showed the V5700's advanced Open GL settings that could be controlled that are only available on FirePro3D cards.

Unfortunately when Catalyst 12.10 came out the new Catalyst Control Center was no longer able to control the old 12.6 driver used with my V5700.  Whenever CCC tried to control the V5700 the system would lock up.

I searched for a solution for a long time and eventually came up with dual booting two copies of the OS (on different partitions).  One boot had the actual V5700 driver installed and the HD6950 disabled, while the other had the opposite.  Unfortunately for some reason with the V5700 disabled and 12.10 running the HD6950 the system remained unstable so eventually I pulled the V5700 and just use the HD6950 with reduced functionality for CAD.  It turns out that the system is still having graphics locking up issues so my HD6950 might be failing (but that is another story...).

For your system are you not just as well off to uninstall the HD3850 and use the HD5870 for both monitors?  I would have thought the HD3850 would have bottlenecked the system (if it was actually being used for graphics processing) and actually produced slower frame rates than just using the HD5870.  Most of the time the AMD driver only uses a single video card for all of the image processing and the second card is only used for displaying what the other generates anyway. 

What I discovered when I was using both cards is that if you use the Catalyst Control Center to configure the displays that the primary display card became also the graphics engine for both cards.  The other card becomes just a display card without any graphics processing.  If instead of using Catalyst to control the cards you used the Windows 7 display management software in the control panel without CCC installed, it could actually be configured to use both graphics chips - but in my case this produced much slower results than using the HD6950's chip for both displays.

I forgot to check on this thread, thanks a lot for the info guys, I now have a solid idea of whats going on.

As for why im using the 3850, I currently have 3 monitors and I know my 5870 can output to 3, but in order to get a 3rd monitor to work I need an active displayport to dvi adapter. Iv tried passive ones, even passive ones that are "approved" by AMD with little luck. So id need to dish the $100-$150 on a proper active displayport adapter. I figured its just easier to throw my old 3850 in and start saving for a proper IPS panel with more inputs.

I have an old 8800 sitting around, could I possibly throw that in and just use it for my other monitors? Im not sure if using nvidia and AMD drivers would cause conflicts. 

In theory it should work as AMD and nvidia drivers are completely different. With using some hacks you could even use that 8800 for physix.

CPU: AMD Phenom II X4 810 @ 3250MHz | RAM: Kingmax 2x2GB DDR2 800 @ 833MHz| MoBo: MSI K9A2 CF v1.0 (BIOS: 1.D)| GPU: Asus HD 6850 1024MB (DirectCu) @ 850/1100MHz | Display: Chili Green Vision L24FHD | PSU: PC Power & Cooling Silencer 750 Quad | OS: MS Windows 95 x64 Edition

CPU: Pentium 4 Northwood S478 @ 3200MHz | RAM: 1,5GB DDR 400| MoBo: Gigabyte GA-8S661FXMP-RZ | GPU: Abit Geforce Ti 4200 | Display: Dimarson 19" CRT | PSU: Noname 400W | OS: MS Windows XP Pro, Fedora 18

I can confirm that in Windows 7, you can have an AMD card and nVidia card hooked up to two different monitors at the same time.  I don't see why that functionality wouldn't extend to more than two.

That said, only adapters for Dual-Link DVI fit into the $100+ price range (they used to be about $80).  For a normal DVI-D connection, the price hovers around $30 or so.  Both this StarTech and Accel from Amazon will work for a monitor with a resolution up to 1920x1200. 

Plausible reasons to use the 8800 instead would include hardware PhysX acceleration (with a few hoops to go through), and the mild performance decrease in games that comes with attaching multiple monitors to the 5870.  The one stat I have readily available for the latter is with the Heaven 2.1 benchmark and two displays attached.  With both displays enabled, the results were about 2.5% lower than they were with just one.

The main reason to use the adapter instead would be power consumption.  An 8800 at idle doesn't clock down, and consumes quite a bit more power than an active DP adapter that gets all it needs from the DP port itself.

Great, thanks for the info guys. Im going to throw it as soon as I find the time.

I just found the card and its actually a 8600GT which will be fine for what I need it for and consume much less power. I don't think this card will even be of much use in PhysX, probably not worth setting it up.

As for adapters, I actually had that Accel adapter and still do. It would work great for a month and then crapped out on me. So they sent me a new one and this one has issues working properly when im playing a game. Like I said, I have only had bad luck with adapters in the past.