As someone has probably already pointed out, new beta drivers are out but here's the link :-http://support.amd.com/us/kbarticles/Pages/AMDCatalyst1211betadriver.aspx
The good news. The segfault starting steam has gone, so no more need to start steam in gdb to workaround it.
Unfortunately the kernel module doesn't compile cleanly against 3.7.0 (which ubuntu 12.10 installed for me recently)
The patch that caused it is detailed here :-https://patchwork.kernel.org/patch/1258951/
Steps I did to workaround the problem
Download and extract amd-driver-installer-catalyst-12.11-beta11-x86.x86_64.run
> ./amd-driver-installer-catalyst-12.11-beta11-x86.x86_64.run --keep --listpkg
> cd fglrx-install.hk4603/
Note, the hk4603 will be different on your system
> vi common/lib/modules/fglrx/build_mod/firegl_public.c
:%:s/VM_RESERVED/VM_DONTEXPAND | VM_DONTDUMP/g
>./ati-installer.sh 9.01.8 --buildpkg Ubuntu/quantal
that should successfully build the package
> cd ..
> sudo dpkg -i fglrx_9.010-0ubuntu1_amd64.deb fglrx-amdcccle_9.010-0ubuntu1_amd64.deb
This should now compile the kernel modules cleanly against 3.7
I have to admit to doing the substitution without looking too closely at the code, it could be that VM_RESERVED could just be removed, or VM_IO would make better sense. I went for the clean compile first and figured I'd pick up any pieces, I haven't really noticed any adverse effects.
Presumably ubuntu ppa and / or distro maintainers may release beta11 with this change already done soon (maybe they already have)
Now the not so good news.
There's no improvement over beta 8 performance that I could see. It's quite a step up from the earlier betas though. But TF2 12v12 public play still remains elusively out of reach. It's about 50% of windows performance in my estimation, which really only hurts in those open areas where it is dipping down to 30-40 fps, enough to make it feel sluggish when you try to aim.
But perhaps there are steam fixes to come? The 'steam using 100% of cpu' hasn't been addressed yet - so unless that's normal behaviour, it may well be the amd drivers are hunky dory now (yeah I can't believe I typed that with a straight face either)