i'm using the windows 7 x64 RC1 on a T500 thinkpad. While the switchable drivers are not yet avaible for w7 i'm switching in bios between the two cards. When Thinkpad On-screen display is installed the boot procedure hangs up (more like the display freezes) after the user login. When automatic startup of osd is disabled everything fine.
Using the wddm 1.1 radeon drivers for the ati card. The intel card boots up with osd right.
I've installed the switchabel drivers, then removed them and used the wddm drivers instead, not sure if it's a driver uninstallation problem (i think its not) or simply the osd takeing over the display
I recently did a clean install of W7 build 7100 (32 bit version) on my W500. I noticed that Microsoft provided a video driver with the OS, and it seemed to work pretty well, so I decided against attempting to install the Lenovo or ATI driver.
The 'gaming graphics' score shown with the Microsoft driver is a wee bit lower than what it was when I was using the most recent Lenovo/ATI driver with Vista SP2, but the desktop graphics score is very high, and most important, the video on the computer performs very well when using the Microsoft supplied driver, even when running DVD or CAD applications. So, I have decided to just disregard the 'video score' and stick with what I know works, that being the Microsoft supplied driver.
Also, concerning the dual graphics capability of the laptop (a 4062-27U in my case), I have found over the past 4 months that there is really very minimal benefit to using the dual graphics capability. In other words, battery life is quite satisfactory for me (about 3 hours) when running the computer on the discrete graphics card and with all the settings at 'high performance'. So, I disabled the integrated graphics in the BIOS, told the computer to just use the discrete graphics all the time, and this has resulted in a much simpler computer than what I got 'out of the box' with the dual graphics capability, and fully satisfactory performance.
I sometimes wonder if we (computer enthusiasts) are masochists - we try and get every single little feature working, even though we don't really need the feature, and this is what causes us the headaches. In my case, since I turned off the fingerprint sensor, integrated graphics, support for legacy serial and parallel connectors and all sorts of other stuff I honestly don't need, the computer has been fast and trouble-free.
I'm not sure if my 32 bit OS experience would apply directly to your efforts with a 64 bit OS. Which also raises the philosophical question "why do we need to run a 64 bit OS anyway?", since the computer operates fine on the 32 bit OS?
W520 (4270 CTO), which replaced a W500 (4062-27U), which replaced a T42P, which replaced an A21P...