das evtl nützlichste was ich durch kurzes googlen gefunfen habe:
Microsoft has now released a HotFix to enable Windows 7 to run on these products in XDDM mode. In order to install Windows 7 on your system with our cards, you need to follow the steps below. This covers Windows 7, Windows 7 64Bit and WinServer 2008 R2.
To begin with please install the hotfix from Microsoft for the Operating System. This hotfix is required for the correct operation and is only available for download from the Microsoft support website:
http://support.microsoft.com/hotfix/KBHotfix.aspx?kbnum=980731&kbln=en-us
Please execute the tool you receive from Microsoft after having registered.
Subsequent to the hotfix installation, install the Matrox device driver. The corresponding driver for your product can be found in the following links, you will need driver version 2.09.158:
For Win7 ftp://ftp.matrox.com/pub/mga/archive/2kxp_2k3_2k8/2010/xddm32_209_00_158_se_u_whql.exe
http://superuser.com/questions/55781/matrox-qid-pcie-lp-and-windows-7-x64