I have the very same problem with HP Probook 450.
I have a Lenovo idea Pad 470P, and I have the similar issue. It doesn't work with latest AMD release driver, and only works for Lenovo published driver, which wasn't updated for a year.
I think the reason could be that the driver Lenovo published is not the exactly the same as AMD published, either Lenovo did some changes or asked AMD build a specific driver for them. I think this should request Lenovo to fix it.
I have understood why this problem happens. And it is solved now for Windows.
This problem arises because of integrated and discrete graphics conflict.
For both of OSs first the driver for integrated card (Intel(R) HD Graphics 4000, in my case) should be properly installed. I took driver from Intel site. The machine must run on the integrated card during these drivers installation.
After this the discrete AMD card should be turned on and the drivers from Lenovo site should be installed. After this the AMD card starts work properly; the latter driver can be installed.
But for OpenSUSE there is a problem with the Intel driver installation. I took the driver's files from OpenSUSE site, done actions written in the README file, but nothing happened.
If anybody knows how to install driver on Intel(R) HD Graphics 4000 under OpenSUSE 12.2, please, help me.
I am also facing problem with AMD RADEON 8750M 2GB ddr3 AGP GPU which actually drove me to buy my new Laptop.
And I am facing trouble with Lenovo G400 Series Notebook , Because of I was offered win 8 OS with this Laptop by my vendor
But when I told him that , I was last using xp pro service pack 3 with my Acer Extensa Zxxxx , then he told me that
Lenovo G400 series will no way support xp pro service pack 3 , the only safer way and best output can be done if I
choose win 7 Ultimate, So I said him okay. But After fixing everything my vendor failed to install the AMD 2GB GPU
he tried in several way with failure and then I said him that I will fix that myself , but after researching 2 days all alone
for fixing this I become some kinda desperate. I think some thing is wrong either with AMD GPU end, or OS end or
my Laptop Manufacture end. And whatever they are lack of in completing, but I am or all customer who will downgrade
will suffer. So if anyone reply me with a stable and professional solution then it will stop wasting time of others.