Quad Monitor setup in Windows 7 only shows 3 displays

[fowldogs]

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.

Thanks,

Roger

 

[fowldogs]

anyone?

 

[superunknown98]

Just to be sure, you have 4 monitors all hooked up via DVI?

 

[ViRGE]

It's my understanding that Win7 only natively supports up to 3 monitors, which would explain your problem. Unfortunately I don't know much beyond that.

 

[Qbah]

It's my understanding that Win7 only natively supports up to 3 monitors, which would explain your problem. Unfortunately I don't know much beyond that.

What about the Eyefinity6 Radeons then? You can show 6 desktops on that.

This here:

http://searchsystemschannel.techtarget.com/generic/0,295582,sid99_gci1370128,00.html

Says "up to 10 displays" in Windows 7. I know it's not a MS KB, but hey

As for the OP, are you using extended desktop mode on both cards? Perhaps one is set to clone, the other to extend and it's not working so great then?

 

[MoobyTheGoldenCalf]

I run 4 monitors in Win 7 Pro just fine. I've got a 260GTX & a 8500GT in my system.

 

[ViRGE]

What about the Eyefinity6 Radeons then? You can show 6 desktops on that.

This here:

http://searchsystemschannel.techtarget.com/generic/0,295582,sid99_gci1370128,00.html

Says "up to 10 displays" in Windows 7. I know it's not a MS KB, but hey

As for the OP, are you using extended desktop mode on both cards? Perhaps one is set to clone, the other to extend and it's not working so great then?

Eyefinity is Single Large Surface - to Windows it's only 1 display. In fact I swear I saw an Eyefinity article mentioning the 3 monitor limit, but heck if I can find it right now.

 

[Qbah]

Eyefinity is Single Large Surface - to Windows it's only 1 display. In fact I swear I saw an Eyefinity article mentioning the 3 monitor limit, but heck if I can find it right now.

Perhaps it's 3 monitors per card? MoobyTheGoldenCalf has 4 screens working fine (2 nVidia cards).

Also, perhaps the libraries used for running multiple screens cannot be shared between two different WDDMs? So two Radeons is fine, Radeon and nVidia isn't? No idea though, just a wild guess.

 

[NoQuarter]

It's my understanding that Win7 only natively supports up to 3 monitors, which would explain your problem. Unfortunately I don't know much beyond that.

You know, I do remember now seeing someplace one of the differences between Home Basic, Home Premium, Professional and Ultimate was the number of monitors it would support. It is possible Home is limited to 3 monitors? I know Win7 itself can support more than that though.. but there may be some limitation for Home.