AMD/ATI driver problems on a Dell laptop with attached dual monitors

Question

I have a Dell Precision M4800 laptop with a docking station for two additional monitors. I'm shooting for a "big desktop" setup, with my laptop display and the two external monitors forming one large multi-monitor X screen.
When deciding which video driver I'd need, I did the usual:
$ lspci | grep VGA
01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Venus XT [Radeon HD 8800M Series]
Which is weird, because the M4800 isn't shipped with 8800M cards. Rather, it's shipped with the AMD FirePro M5100 Mobility Pro (see above link) (also, too many "Pros", AMD...).
I tried the open-source driver, but I couldn't get both my external monitors working in tandem, so I went with catalyst-test, since the non-beta version of the proprietary driver doesn't support the 3.13 kernel (or my alleged 8800M series card, for what it's worth).
My display setup using catalyst-test is still far from ideal. My dual (horizontally adjacent) monitors reset to cloned/mirrored desktops after every reboot, and my machine refuses to show three monitors (dual monitors + laptop display), even with the 2GB of dedicated RAM in my graphics card (see above M4800 link). There's other miscellaneous annoyances as well.
Using hardinfo, I see that my VGA driver thinks it only has 256MB of RAM... which doesn't align with the M4800 specs. Is there a way to change this value?
Just today, I found the catalyst-firepro driver, which I think might be the correct driver for my laptop, at least given the specs on the M4800 from the website.
There's also the option of not using my AMD card at all, and just using the Intel graphics on my laptop. (I had to disable hybrid graphics in my BIOS to get any AMD-specific drivers to work). I'd like to steer away from this, due to the performance loss, but I'd be willing to make the change if the pros outweighed the cons.
As I see it, I have a few options:
AMD/ATI open source driver: Can't seem to get two monitors working, much less three...
catalyst-test: Any two monitors will work together, but not three. Other annoyances.
catalyst-firepro: Have not tested yet.
Intel open-source driver with AMD card disabled: Have not tested yet.
Can anyone who has had similar issues and/or hardware offer a best course of action which has worked for them? I know we're supposed to avoid "opinion" questions, but I think this is grounded enough in the scientific method to merit some helpful responses.
Any help is appreciated.
Thanks!

Answer 1

clfarron4 wrote:
The last option to me is screaming catalyst-pxp at me, because that's one of the few options if you have integrated graphics and a discrete graphics card.
Let me get this straight: Can you disable the either or both of the Intel/AMD graphics in the BIOS settings? If so, but don't want to disable either, you might want to look at the hybrid graphics section of the wiki.
I know about powerXpress and I think I'd like to avoid it. My experience with hybrid graphics on other Linux distributions is that it's rather unstable or just plain unsupported. If someone can convince me otherwise, given their experience with hybrid graphics on Arch/Linux, I might reconsider.
I'm fairly certain I can enable either of my GPU's separately, but I'll have to check for sure next I reboot my PC.
The last option I mentioned because I thought the Intel drivers might be more robust than the AMD drivers, which have don't have a sterling reputation when it comes to supporting Linux (compared to nVidia anyways, who I know in the past have had good Linux support).