I have an HP xw8400 workstation running Windows 7 64-bit. This unit came with an Nvidia Quadro 1500 dual-DVI video card.
Recently, I have decided 2 video cards is not enough space and decided to move to quad-monitors. Upon reading different forums, including this one, it seems that Windows 7 will support 2 video cards of different makes and chipsets. I don't do major graphics work that requires high-end video cards. I just need multi-tasking space.
So, I purchased an ATI HD 4550 video card and installed it in the system. Everything installed well and the latest video drivers installed. The workstation is also running the latest bios.
My problem, however, is that I only have 3 monitors showing in display properties. When I have the Quadro 1500 installed as the primary graphics card, the system shows 2 monitors via the dual DVI of the Quadro 1500 and the DVI of the HD 4550.
If I move the HD 4550 to the primary video card, I show 2 monitors via the HD 4550 (one via DVI and one via D-Sub) and then a 3rd monitor from one of the Quadro's DVI ports.
Any ideas why I only see 3 monitors and not 4 in this setup? I have thought about purchasing another HD 4550 to see if that fixes it. But before I spend the money, I wanted to see if any of you have an idea.