Cheaper motherboards with more budget-oriented chipsets might only go up to a single x8 slot, even if that slot can physically accommodate an x16 card. Meanwhile, 'gamer' motherboards will include up to four full x16-size and x16-lane PCI-E slots for maximum GPU compatibility. Cables not included. System Requirements PCIe-based PC with one X16 lane graphics slot available on the motherboard. System Power Supply Required: 500W Operating Systems Supported:. Windows 10 32/64-bit. Windows 8.1 32/64-bit. Windows 7 32/64-bit. Windows Embedded Standard 7 32/64-bit. Windows Server 2012 R2 64-bit. Install this VisionTek Radeon 5450 graphics card in your PCIe computer's X16 lane graphics slot for cost-effective, energy efficient video playback, standard gaming and editing support. The fanless design is easy to install, and the 1GB DDR3 dedicated memory doesn't bog down your system. PCI Express 3.0 is a specification for connectors, data rates and IO. PCI Express x16 is related to the size of the connector (MB socket or card fingers). The x16 means 16 lanes in and 16 lanes out. X1, x2, x4 and x8 are also available. Some x16 slots may allow the larger cards to be used but only have x8 IO connected when shared with other slots.
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Applies to:
- Microsoft Windows Vista
- Microsoft Windows Server 2003
- Microsoft Windows XP
- Microsoft Windows 2000
This paper provides information about PCI Express Graphics for Microsoft Windows operating systems, and answers frequently asked questions.
PCI Express
PCI Express (PCIe) is an I/O bus technology that was designed to replace Peripheral Component Interconnect (PCI), PCI-X, and Accelerated Graphics Port (AGP). By providing advanced features and increased bandwidth, PCIe addresses many of the shortcomings of PCI, PCI-X, and AGP. PCIe retains full software compatibility with PCI Local Bus Specification 2.3, and it replaces the parallel multidrop bus architecture of PCI and PCI-X with a serial, point-to-point connection bus architecture.
Two PCIe devices are connected by a link, and each link is made up of one or more lanes. Each lane consists of two low-voltage, differential signal pairs carrying 2.5 Gbps of traffic in opposite directions. One pair is used for transmitting, and the other pair is used for receiving. To further increase the bandwidth of a link, multiple lanes can be placed in parallel (x1, x2, x4, x8, x12, x16, or x32 lanes) between two PCIe devices to aggregate the bandwidth of each individual lane.
PCIe hardware is backwards compatible with PCI software on the Microsoft Windows 2000 and Microsoft Windows XP operating systems. Advanced PCIe features are natively supported only in Windows Vista and later versions of Windows.
Definitions
XPDM: The Windows XP Display Driver Model.
WDDM: The Windows Vista Display Driver Model. WDDM is a significant evolution of the graphics driver infrastructure and is backwards compatible with XPDM drivers.
GART: Graphics address relocation table, hardware that presents the display adapter with a linearized view of nonlinear memory.
DCT: Display compatibility tests. Video drivers need to pass these tests in order to comply with the Windows Certification Program and be digitally signed by Microsoft.
WHQL: Windows Hardware Quality Laboratories. The organization within Microsoft that is responsible for the Windows Certification Program for hardware.
PCI Express Graphics
It is well known that graphics can always use more bandwidth than what is available. Graphics data transfers cause maximum traffic on the PCI bus. The continual increase in graphics demand and complexity eventually made the PCI bus insufficient, which led to the invention of AGP. Now we are pushing the limits of what AGP can deliver, and we need a better solution. PCIe surpasses AGP in bandwidth availability, with more room for expansion in the near future. By increasing the number of lanes in a link, graphics adapters can take advantage of increased bandwidth and faster data transfer. For example, a graphics adapter that uses an X16 link has bandwidth of 4 Gbps in each direction.
Given the higher bandwidth offered by PCIe, systems are already moving away from AGP to PCIe. Typically, a system does not provide both AGP and PCIe connectors.
PCI Express Graphics in Windows Vista
The Windows Vista Display Driver Model (WDDM) has specific requirements for PCIe graphics adapters, for example that the 64-bit addressing mode be supported by the GPU. However, a minimum of 40 bits of physical address bits must be implemented. The unimplemented bits should be forced to zero. These requirements are not applicable to the Windows XP display driver model.
PCIe Graphics & AGP
In addition to the bandwidth considerations mentioned above, there are several other differences between AGP and PCIe.
By definition, AGP requires a chipset with a graphics address relocation table (GART), which provides a linear view of nonlinear system memory to the graphics device. PCIe, however, requires that the memory linearization hardware exist on the graphics device itself instead of on the chipset. Consequently, driver support for memory linearization in PCIe must exist in the video driver, instead of as an AGP-style separate GART miniport driver. Graphics hardware vendors who want to use nonlocal video memory in their Windows XP driver model (XPDM) drivers must implement both memory linearization hardware and the corresponding software. All PCIe graphics adapters that are compatible with the WDDM must support memory linearization in hardware and software.
Pcie Speeds Explained
AGP was dedicated to graphics adapters, and no other device class used it. PCIe is intended to be used by all device classes that previously used PCI. With AGP, a number of video drivers were directly programming the chipset, which gave rise to severe ill effects such as crashing and memory corruption in the graphics stack. Because PCIe will be used for all devices in the system, it is even more important that video drivers not program the chipset directly.
Frequently Asked Questions
Will a PCIe video card work on Windows XP? Yes. PCIe is software compatible with PCI. PCIe hardware works on operating systems that support PCI.
Does PCIe graphics coexist with AGP? Some chipsets support both AGP and X16 PCIe. Some motherboards have both AGP and X16 PCIe slots using such a chipset.
Will multimonitor configurations work on PCIe graphics? Multimonitor configurations of PCIe are expected to work just like PCI. Whether they do will depend on the motherboard manufacturers. For example, x16, x8, and x8 triple monitor configuration will necessitate the existence of one x16 and two x8 slots on the motherboard.
What are the performance implications of using PCIe Graphics? High-speed PCIe graphics solutions have better performance than AGP. Typically, PCIe graphics cards use the x16 PCIe slot. This translates into a bandwidth of 4 Gbps. This is already a twofold increase over AGP 8X. In this case, 'x1' means that the slot has one PCIe lane, which will give it a bandwidth of 264 Mbps. This is equal to the bandwidth provided by AGP 1X and twice that of PCI (132 Mbps).
| PCIe version | AGP | Bandwidth |
|---|---|---|
| PCIe x1 | AGP 1X | 264 Mbps |
| PCIe x4 | AGP 4X | 1 Gbps |
| PCIe x8 | AGP 8X | 2 Gbps |
| PCIe x16 | 2 x AGP 8X | 4 Gbps |
Additionally, the AGP specification does not support 'snooping.' It implies that memory used by devices needs to be mapped uncached or write combined by the processor in order to prevent the processor from caching that memory, or else an expensive cache flush needs to be done between handoff of a surface between CPU and GPU. Thus, processor read access to that memory will be very slow.
PCIe will support snooping. It will now be possible to map such shared memory as cacheable and still be able to maintain coherency between the CPU and the GPU. Snooped transactions are slower than nonsnooped transactions, but since the CPU can read the shared memory at full speed and we do not need to flush any caches, the tradeoff might mean better performance in some scenarios.
Is an n-lane PCIe slot compatible with a p-lane PCIe graphics card, where p > n? Where n > p? You cannot plug an x16 graphics card into an x8 slot. You can however, if you wish, plug an x8 card PCIe card into an x16 slot. A p-lane PCIe card will work at some speed in an n-lane PCIe slot, where n > p. This is not true if n < p.
Related topics
How Many PCIe Lanes Do You Really Need?
With the new line of X570 motherboards coming up, PCIe 4.0 is finally within reach for the average consumer. With that in mind, it seemed like a good idea to talk about PCIe lanes. What are they exactly, and how many lanes do you really need?
First, a refresher: PCIe 3.0 is the current expansion bus standard used on most modern motherboards. It's the hardware interface between devices (e.g., video cards, sound cards, M.2 drives, network cards) and the motherboard. The slots come in various sizes (x1, x2, x4, x8, and x16)1, and the speed of a given slot is determined by the number of available PCIe lanes.
The total number of lanes for a slot are broken up into thesame numbers as above (1, 2, 4, 8, 16). However, to make things slightly
confusing, the number of lanes in a slot does not always match the physical slot length. Meaning, you can (and often do) encounter a x16 slot with only 8 lanes. Pro-tip: you can actually see this by looking for the shiny little contacts in the slot itself. If the contacts only go up halfway, that x16 slot only has 8 lanes.
But 8 lanes are often plenty. Even though the theoretical data transfer limits of 8 and 16 lane slots are vastly different2, there is currently no consumer card on the market capable of saturating the bandwidth of a PCIe 3.0 x16 slot. While the amount of data being 'crunched' by a high-end video card is often above that limit, the majority of calculations related to the device are actually handled by the card's internal processor, and therefore do not need to travel through the bus. Performance differences are mainly dependent on the card itself, and not the theoretical limits of the slot.
Motherboards are designed with various amounts of PCIe lanes, and different processors are designed with support for certain amounts of lanes. Server and enthusiast boards are typically designed with more lanes to provide more expandability, and CPU manufacturers segment their products similarly. For example, the Intel Core i7-9700K supports a maximum of 16 lanes, while the Core i9-9980XE supports a maximum of 44. But bigger is not always better—the processors are simply designed for different environments.
Pcie Lanes Explained
However, to complicate things further, there is such a thing known as a PCI Express Switch, which is a chip on some motherboards that is often said to double the number of lanes, but this is not strictly accurate. While it does not magically create more, it does alter how the CPU manages signals to the slots via signal multiplexing. In short, it changes how data is sent and received from the CPU to the PCIe slots in order to utilize the same number of lanes more dynamically across devices to achieve better performance.
Back to the topic at hand: the number of lanes you need depends on how many PCIe devices you want to use in your system, and how fast you want all those devices to run, though noticeable effects on performance usually only occur in niche configurations. A single GPU runs best with 16 lanes. When installing an additional GPU, be sure to use a x16 slot with 16 lanes, if possible. Conversely, if you are adding a x4 card and only have a x8 slot available, that will work too. All PCIe 3.0 slots are compatible with smaller form factor devices, assuming they physically fit into the slot.
Any time you dive into a technology topic, it's easy to become overwhelmed. Luckily, BOXX has done all the research for you and designed workstations to fit any workflow. The APEXX S3, our flagship workstation, is designed for single-threaded applications that run at peak efficiency with a single high-end GPU. However, if you require that same unmatched overclocked processor (8 cores at 5.1GHz) but require more PCIe lanes, the APEXX Enigma S3 is the perfect option. Or if you need even more space, the APEXX S4 has enough lanes to run four dual-width GPUs.
Pcie Speeds Explained
AGP was dedicated to graphics adapters, and no other device class used it. PCIe is intended to be used by all device classes that previously used PCI. With AGP, a number of video drivers were directly programming the chipset, which gave rise to severe ill effects such as crashing and memory corruption in the graphics stack. Because PCIe will be used for all devices in the system, it is even more important that video drivers not program the chipset directly.
Frequently Asked Questions
Will a PCIe video card work on Windows XP? Yes. PCIe is software compatible with PCI. PCIe hardware works on operating systems that support PCI.
Does PCIe graphics coexist with AGP? Some chipsets support both AGP and X16 PCIe. Some motherboards have both AGP and X16 PCIe slots using such a chipset.
Will multimonitor configurations work on PCIe graphics? Multimonitor configurations of PCIe are expected to work just like PCI. Whether they do will depend on the motherboard manufacturers. For example, x16, x8, and x8 triple monitor configuration will necessitate the existence of one x16 and two x8 slots on the motherboard.
What are the performance implications of using PCIe Graphics? High-speed PCIe graphics solutions have better performance than AGP. Typically, PCIe graphics cards use the x16 PCIe slot. This translates into a bandwidth of 4 Gbps. This is already a twofold increase over AGP 8X. In this case, 'x1' means that the slot has one PCIe lane, which will give it a bandwidth of 264 Mbps. This is equal to the bandwidth provided by AGP 1X and twice that of PCI (132 Mbps).
| PCIe version | AGP | Bandwidth |
|---|---|---|
| PCIe x1 | AGP 1X | 264 Mbps |
| PCIe x4 | AGP 4X | 1 Gbps |
| PCIe x8 | AGP 8X | 2 Gbps |
| PCIe x16 | 2 x AGP 8X | 4 Gbps |
Additionally, the AGP specification does not support 'snooping.' It implies that memory used by devices needs to be mapped uncached or write combined by the processor in order to prevent the processor from caching that memory, or else an expensive cache flush needs to be done between handoff of a surface between CPU and GPU. Thus, processor read access to that memory will be very slow.
PCIe will support snooping. It will now be possible to map such shared memory as cacheable and still be able to maintain coherency between the CPU and the GPU. Snooped transactions are slower than nonsnooped transactions, but since the CPU can read the shared memory at full speed and we do not need to flush any caches, the tradeoff might mean better performance in some scenarios.
Is an n-lane PCIe slot compatible with a p-lane PCIe graphics card, where p > n? Where n > p? You cannot plug an x16 graphics card into an x8 slot. You can however, if you wish, plug an x8 card PCIe card into an x16 slot. A p-lane PCIe card will work at some speed in an n-lane PCIe slot, where n > p. This is not true if n < p.
Related topics
How Many PCIe Lanes Do You Really Need?
With the new line of X570 motherboards coming up, PCIe 4.0 is finally within reach for the average consumer. With that in mind, it seemed like a good idea to talk about PCIe lanes. What are they exactly, and how many lanes do you really need?
First, a refresher: PCIe 3.0 is the current expansion bus standard used on most modern motherboards. It's the hardware interface between devices (e.g., video cards, sound cards, M.2 drives, network cards) and the motherboard. The slots come in various sizes (x1, x2, x4, x8, and x16)1, and the speed of a given slot is determined by the number of available PCIe lanes.
The total number of lanes for a slot are broken up into thesame numbers as above (1, 2, 4, 8, 16). However, to make things slightly
confusing, the number of lanes in a slot does not always match the physical slot length. Meaning, you can (and often do) encounter a x16 slot with only 8 lanes. Pro-tip: you can actually see this by looking for the shiny little contacts in the slot itself. If the contacts only go up halfway, that x16 slot only has 8 lanes.
But 8 lanes are often plenty. Even though the theoretical data transfer limits of 8 and 16 lane slots are vastly different2, there is currently no consumer card on the market capable of saturating the bandwidth of a PCIe 3.0 x16 slot. While the amount of data being 'crunched' by a high-end video card is often above that limit, the majority of calculations related to the device are actually handled by the card's internal processor, and therefore do not need to travel through the bus. Performance differences are mainly dependent on the card itself, and not the theoretical limits of the slot.
Motherboards are designed with various amounts of PCIe lanes, and different processors are designed with support for certain amounts of lanes. Server and enthusiast boards are typically designed with more lanes to provide more expandability, and CPU manufacturers segment their products similarly. For example, the Intel Core i7-9700K supports a maximum of 16 lanes, while the Core i9-9980XE supports a maximum of 44. But bigger is not always better—the processors are simply designed for different environments.
Pcie Lanes Explained
However, to complicate things further, there is such a thing known as a PCI Express Switch, which is a chip on some motherboards that is often said to double the number of lanes, but this is not strictly accurate. While it does not magically create more, it does alter how the CPU manages signals to the slots via signal multiplexing. In short, it changes how data is sent and received from the CPU to the PCIe slots in order to utilize the same number of lanes more dynamically across devices to achieve better performance.
Back to the topic at hand: the number of lanes you need depends on how many PCIe devices you want to use in your system, and how fast you want all those devices to run, though noticeable effects on performance usually only occur in niche configurations. A single GPU runs best with 16 lanes. When installing an additional GPU, be sure to use a x16 slot with 16 lanes, if possible. Conversely, if you are adding a x4 card and only have a x8 slot available, that will work too. All PCIe 3.0 slots are compatible with smaller form factor devices, assuming they physically fit into the slot.
Any time you dive into a technology topic, it's easy to become overwhelmed. Luckily, BOXX has done all the research for you and designed workstations to fit any workflow. The APEXX S3, our flagship workstation, is designed for single-threaded applications that run at peak efficiency with a single high-end GPU. However, if you require that same unmatched overclocked processor (8 cores at 5.1GHz) but require more PCIe lanes, the APEXX Enigma S3 is the perfect option. Or if you need even more space, the APEXX S4 has enough lanes to run four dual-width GPUs.
Those are just a few examples. Regardless of your specific needs, BOXX has a workstation with your workflow in mind. Talk to a BOXX Performance Specialist today to learn more.
Pcie Channels
1 Technically x32 slots do exist, but they're very rare.
Pcie Link Speed Gpu
2 7,880MB/s and 15,760MB/s, respectively.
