A word of warning to anybody considering using Matrox multihead cards on Linux or other Unix boxes. Matrox is being less than honest with this statement from the Matrox page for the Millennium G550 PCIe x1 http://www.matrox.com/mga/workstation/3dws/products/mill_gseries/g550_pcie.cfm For the older cards (G200, G450 etc), their drivers use the open source XFree86/Xorg mga drivers PLUS a so called HAL (hardware abstraction layer) binary only module that Matrox refuse to release the source to. You need the HAL module to use more than one head or DVI. Hardly open source by anyone's standards. The drivers for the newer cards are also not open source. The upshot is that Linux is poorly supported. For example no support for anything other than 32 bit x86. While 64 bit might be lagging in the Windows world it is becoming widely used in the Linux domain. If the drivers were open source as Matrox falsely claim, the 64 bit port would have been done long ago. Matrox executives should read the Linux support forums on their own website. For a company with a reputation for quality products, it makes depressing reading. Nvidia, on the other hand while not open sourcing their drivers are at least taking the issue seriously and producing decent drivers for Linux. They are fast and they work and there is x86 64 bit support.