- Joined
- Jan 30, 2008
So after the recent price cuts on the GX2's, I really started to read into using a multiple GPU card, and a 2nd card for a 2nd monitor. Here is a blurb straight off of Microsoft's website. Sorry about the length:
"
Homogeneous Multi-adapter
Multi-adapter refers to the use of more than one graphics adapter in a single PC. The term "homogeneous multi-adapter" is used to refer to cases when more than one graphics adapter is in use but all adapters use the same graphics driver.
Here are two examples:
•
Two identical cards from the same graphics hardware vendor - for example, two PCIe ATI Radeon x600 cards, each in an x16 PCIe slot.
•
Two different cards from the same graphics hardware vendor - for example, one PCIe NVIDIA GeForce 7600 in an x16 slot and another PCIe NVIDIA GeForce 6600 in a second x16 slot.
Notice that the bus type - PCIe, AGP, or PCI - is irrelevant. You could have "n" cards in "n" PCIe slots of the same or different lane widths, or you could have "n-m" cards in PCIe slots and "m" cards in PCI slots. The key point to remember is that all "n" graphics adapters use a single graphics driver.
Heterogeneous Multi-adapter
The term "heterogeneous multi-adapter" is used to refer to multiple graphics adapters using multiple graphics drivers in a single PC. A common example is the use of graphics adapters from two different manufacturers, each of which requires a different graphics driver from the respective manufacturer.
Top of pageTop of page
Multimonitor Support before WDDM
Although Windows NT 4.0 did not have native multi-monitor support in the operating system, graphics hardware vendors could incorporate some level of support through their customized graphics drivers, software utilities, or both.
Windows 2000 provided some native support for management of multiple displays to present the desktop. Windows XP took this a step further through the Windows XP Display Driver Model (XPDM) to support multiple graphics cards natively and provided the hardware vendors with the proper means to offer support in their drivers.
Top of pageTop of page
Multimonitor Support in WDDM
On Windows Vista, older XPDM drivers still work and the multi-monitor behavior with XPDM drivers hasn't changed, because the operating system uses the legacy graphics stack.
However, the Windows Vista Display Driver Model (WDDM) brings fundamental changes to the management of multiple graphics adapters and external displays. This includes a new restriction, because WDDM drivers do not support "heterogeneous multi-adapter" multi-monitor implementations. Specifically:
•
All graphics adapters in a system must use the same display driver model. That is, all of them should either be running XPDM or WDDM. The driver models are mutually exclusive, and Windows Vista does not allow the simultaneous loading of both an XPDM driver and a WDDM driver.
If a system has one graphics adapter with a XPDM driver and another with a WDDM driver, then Windows Vista will choose the POST device, which is the one with VGA resources. This is commonly referred to as the "VGA adapter."
•
If multiple graphics adapters are present in a system, all of them must use the same WDDM driver. If there are two graphics adapters with WDDM drivers from two different manufacturers, then Windows will disable one of them. The VGA adapter will be enabled, and the second device will be disabled.
Notice that XPDM drivers still support heterogeneous multi-adapter as they did in Windows XP. A user who has such a configuration working fine in Windows XP will encounter a problem when upgrading to Windows Vista. An external monitor connected to one of the graphics adapters will have no video signal, because it is disabled. An error message will appear on system boot, as described later in this article.
The solution for this problem could be as follows:
•
A user could force the installation of a XPDM driver for each of these devices, and therefore get heterogeneous multi-adapter multi-monitor to work as in Windows XP.
-Or-
•
The user could change the graphics hardware configuration by choosing multiple graphics adapters that use the same WDDM driver. Graphics adapters from the same ASIC family generally have the same graphics driver. In late 2006, each of the major graphics vendors had a single WDDM driver for all supported WDDM graphics adapters. Please consult the graphics vendor's Web site for details on their driver support.
"
Now I'm confused as hell after reading that. But let me ask some experts knowledge here and see if I have it straight.
I have a 9800GX2 in PCI-E slot running, running with it's SLI enabled, running on 175.16 drivers, powering my 24" monitor. Now in PCI-E slot number 2, I have something like this card, using the same 175.16 driver, powering my 2nd monitor. Per that Microsoft article, would that work? Would the fact that one is SLI enabled matter? Does anyone have experience with this, dual monitors in a SLI environment? Thanks in advance
"
Homogeneous Multi-adapter
Multi-adapter refers to the use of more than one graphics adapter in a single PC. The term "homogeneous multi-adapter" is used to refer to cases when more than one graphics adapter is in use but all adapters use the same graphics driver.
Here are two examples:
•
Two identical cards from the same graphics hardware vendor - for example, two PCIe ATI Radeon x600 cards, each in an x16 PCIe slot.
•
Two different cards from the same graphics hardware vendor - for example, one PCIe NVIDIA GeForce 7600 in an x16 slot and another PCIe NVIDIA GeForce 6600 in a second x16 slot.
Notice that the bus type - PCIe, AGP, or PCI - is irrelevant. You could have "n" cards in "n" PCIe slots of the same or different lane widths, or you could have "n-m" cards in PCIe slots and "m" cards in PCI slots. The key point to remember is that all "n" graphics adapters use a single graphics driver.
Heterogeneous Multi-adapter
The term "heterogeneous multi-adapter" is used to refer to multiple graphics adapters using multiple graphics drivers in a single PC. A common example is the use of graphics adapters from two different manufacturers, each of which requires a different graphics driver from the respective manufacturer.
Top of pageTop of page
Multimonitor Support before WDDM
Although Windows NT 4.0 did not have native multi-monitor support in the operating system, graphics hardware vendors could incorporate some level of support through their customized graphics drivers, software utilities, or both.
Windows 2000 provided some native support for management of multiple displays to present the desktop. Windows XP took this a step further through the Windows XP Display Driver Model (XPDM) to support multiple graphics cards natively and provided the hardware vendors with the proper means to offer support in their drivers.
Top of pageTop of page
Multimonitor Support in WDDM
On Windows Vista, older XPDM drivers still work and the multi-monitor behavior with XPDM drivers hasn't changed, because the operating system uses the legacy graphics stack.
However, the Windows Vista Display Driver Model (WDDM) brings fundamental changes to the management of multiple graphics adapters and external displays. This includes a new restriction, because WDDM drivers do not support "heterogeneous multi-adapter" multi-monitor implementations. Specifically:
•
All graphics adapters in a system must use the same display driver model. That is, all of them should either be running XPDM or WDDM. The driver models are mutually exclusive, and Windows Vista does not allow the simultaneous loading of both an XPDM driver and a WDDM driver.
If a system has one graphics adapter with a XPDM driver and another with a WDDM driver, then Windows Vista will choose the POST device, which is the one with VGA resources. This is commonly referred to as the "VGA adapter."
•
If multiple graphics adapters are present in a system, all of them must use the same WDDM driver. If there are two graphics adapters with WDDM drivers from two different manufacturers, then Windows will disable one of them. The VGA adapter will be enabled, and the second device will be disabled.
Notice that XPDM drivers still support heterogeneous multi-adapter as they did in Windows XP. A user who has such a configuration working fine in Windows XP will encounter a problem when upgrading to Windows Vista. An external monitor connected to one of the graphics adapters will have no video signal, because it is disabled. An error message will appear on system boot, as described later in this article.
The solution for this problem could be as follows:
•
A user could force the installation of a XPDM driver for each of these devices, and therefore get heterogeneous multi-adapter multi-monitor to work as in Windows XP.
-Or-
•
The user could change the graphics hardware configuration by choosing multiple graphics adapters that use the same WDDM driver. Graphics adapters from the same ASIC family generally have the same graphics driver. In late 2006, each of the major graphics vendors had a single WDDM driver for all supported WDDM graphics adapters. Please consult the graphics vendor's Web site for details on their driver support.
"
Now I'm confused as hell after reading that. But let me ask some experts knowledge here and see if I have it straight.
I have a 9800GX2 in PCI-E slot running, running with it's SLI enabled, running on 175.16 drivers, powering my 24" monitor. Now in PCI-E slot number 2, I have something like this card, using the same 175.16 driver, powering my 2nd monitor. Per that Microsoft article, would that work? Would the fact that one is SLI enabled matter? Does anyone have experience with this, dual monitors in a SLI environment? Thanks in advance
