NVIDIA SLI u PCB circuit board connecting card
At Computex2004 Taipei Computer Show in 2004, nVIDIA showed NV45 graphics card to the outside world. NV45 is actually the PCI Express version of GeForce 6800, and it is realized by HSI bridge chip, so there is not much difference between NV45 and GeForce 6800. However, a mysterious interface appeared on the top of the NV45 sample card. At that time, no one knew its purpose, and Invista did not disclose it. In fact, the mysterious interface is used to interconnect two graphics cards to form a SLI dual graphics card parallel system.
We can see that the SLI interconnection of NV45 no longer relies on cables like Voodoo 2, but uses a PCB with "MIO" interfaces at both ends to connect daughter cards. The interface on the card is somewhat similar to PCI Express× 1, while the corresponding interface remains at the top of the graphics card. In this way, the SLI connection card can connect two NV45 graphics cards to realize the parallel operation of SLI. NVIDIA said that the selection of PCB card connection can fully guarantee the quality and speed of signal communication, and the data transmission between graphics cards is carried out in digital form, which can effectively prevent the disadvantages of unsynchronized pictures caused by signal interference. Voodoo 2 adopts analog transmission mode, and the digital signal is first converted into analog signal and then synthesized. Due to the influence of interference, there will be data mismatch at some time, which often leads to difficulties in synchronization or other problems after synthesis, which is also the main defect of Voodoo 2 SLI technology. When using digital signal transmission, this problem obviously does not exist. The frame data processed by the graphics card is assembled and synthesized, and then converted into analog signals for output, which ensures the integrity of the picture.
NVIDIA SLI multi-GPU is really a crazy graphics display technology. No matter how demanding 3D games are, they can cope with exaggerated special effects. Game lovers can fully experience the pleasure of greatly improving the speed and display effect. For professional designers, SLI can also double the efficiency-you must have heard that rendering is time-consuming and laborious. In order to render a short virtual picture, the graphics workstation may run continuously for several hours until several days and nights. With SLI, the rendering time can be almost halved and the efficiency is greatly improved.
Through this advanced SLI technology, we can get almost twice the graphic display performance, and it is no longer unrealistic to introduce it into practical application. It is no longer as expensive as Voodoo 2 SLI. Recently, NVIDIA released the latest driver, which can turn on the SLI function in the standard version of Geforce6600, and ordinary consumers can easily embody this advanced technology without connecting a bridge. On the one hand, this is due to the pressure brought by ATi crossfire. In the long run, NVIDIA can work hard on load balancing algorithm and core development. This SLI technology and market positioning will continue to develop, so that more consumers can easily establish their own SLI systems. For example, the old and new graphics cards can work together in SLI mode, and users only need to buy faster graphics cards when upgrading to build a SLI system. The development prospect of SLI is bright. If SLI can be popularized, it will have a far-reaching impact on the whole graphics card market.
For this reason, nVIDIA has developed a set of dynamic load balancing technology, which is not a fixed half-way to divide the picture up and down, but according to the complex situation of the picture, such as 4: 5 or 3: 2 and other unequal modes. This distribution is not to ensure the absolute average distribution of workload between two graphics cards, but to keep the time for two graphics cards to complete rendering tasks consistent, so as to achieve the optimization of efficiency. Considering that the main graphics card needs to undertake additional control tasks and has less resources for actual rendering operations, the dynamic load balancing algorithm can share more tasks to the auxiliary cards according to this premise. In this way, the SLI system built by NVIDIA can ensure that both graphics cards work at the best efficiency. It should be mentioned that this dynamic load balancing algorithm is not integrated in the GPU chip, but integrated in the driver, and nVIDIA can easily modify it to provide better performance.
The following is the process of this dynamic load balancing technology to balance various renderings:
However, this dynamic balance technology is not omnipotent. NVIDIA SLI can't support the construction of parallel system between different graphics cards, and V-Sync (vertical synchronization) of upper and lower pictures is also a problem when two graphics cards work together. If this function is turned on, it will definitely have a certain impact on the game performance. However, NVIDIA said that the cache technology has been adopted to solve this problem, and the two graphics cards also support overclocking after the SLI working mode is established, but the frequencies of the two graphics cards must be exactly the same.
SLI technology of Voodoo 2 uses frame lines to divide tasks: a rendered image is divided into two parts: odd rendered frames and even rendered frames, and then rendered by two graphics cards respectively, and then synthesized uniformly. Although nVIDIA continues to use the name "Extensible Link Interface", its working mode has been fundamentally different. In nVIDIA's SLI system, the rendered image is divided into upper and lower parts. The main graphics card completes the upper part of the screen, and the auxiliary graphics card completes the lower part. Then the auxiliary graphics card transmits the rendered picture to the main graphics card, and the main graphics card synthesizes it with the upper half of the rendered picture into a complete picture. In this way, a complete SLI parallel rendering task is completed. Similarly, if there are four GPUs running in parallel, the picture will be divided into four parts and rendered separately, as will eight GPUs running in parallel.
Voodoo 2 traditional odd-even division of labor
NVIDIA SLI intelligent division of labor
The traditional multi-GPU technology mostly adopts the way of task sharing, and the rendering tasks completed by the two graphics cards are completely equivalent, which is the case with the SLI of Voodoo 2 and Voodoo 5 series, and the ATi of XGI and MAXX graphics cards of Volari Duo series also adopt similar ideas. However, the design of average task allocation is unscientific: first of all, the main graphics card or main GPU must undertake additional work such as control, task allocation, picture composition, output, etc., and the computing resources used for rendering are less, but it must complete as many tasks as the auxiliary cards. Naturally, the secondary card takes the lead in completing the task, and after returning the result data, it is in a waiting state, and the task allocation cannot be continued until the primary card finishes processing these tasks; Secondly, the complexity of different areas of the same picture is different, and the amount of calculation required is also different. It's nothing if Voodoo 2' s frame line division method is used, but nVIDIA's SLI adopts the method of dividing up and down pictures. For example, in a common racing game, the upper part of the screen is almost static, while the lower part is very complicated, and the amount of data to be processed is very large. Simply dividing the picture equally is unscientific.
The above introduction is only the most superficial feature of SLI, and the real key lies in the operating mechanism of this system. SLI's two graphics cards are different. One graphics card serves as the master graphics card and the other as the slave graphics card. Among them, the main card is responsible for the operation and control of task allocation, rendering, post-synthesis, output, etc., while the auxiliary card only receives tasks from the main card for related processing, and then sends the results back to the main card. Here, we need to be clear about two data transmission methods. Both graphics cards are connected to the motherboard through PCI Express interface, and there is a communication PCB card between the two cards. Among them, the PCB card connected with two graphics cards is used to transmit task assignment instructions and post-processing results, and the amount of data in this part is not very large, so the interface and its own structure used by the PCB card are relatively simple. However, the graphics card must call a lot of data in the process of rendering, which can only be obtained from the system through PCI Express interface. In other words, there are two different data streams in the SLI system. One part is that the main card sends task instructions to the secondary card through the PCB connection card, and the secondary card returns the rendering result data to the main card for synthesis. The other part is the original data obtained from PCI Express interface during processing.
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What is SLI? How does it work?
Sli (Flexible and Scalable Interface) is a technology aimed at achieving high performance, which allows users to skillfully combine and improve the performance of graphics chips by configuring multiple NVIDIA GPU in a system. The working principle of SLI is to improve the geometric and fill rate performance of two GPUs in an intelligent way.
What's the difference between SLI and competitors' products?
SLI improves the multi-GPU configuration based on PCI Express technology to a new level by designing a series of GPUs with intelligent hardware and software technologies, and these technologies will be patented soon. So that PC and workstation can achieve unprecedented performance.
Do you have hardware dedicated to NVIDIA SLI, or just software?
Yes, the combination of GeForce GPU and nForce4 SLI motherboard (with NVIDIA's proprietary SLI connector) is a very necessary component of SLI. We have a special extended logic scheme in each GPU, and there are digital interfaces between multiple GPUs, which is helpful to realize these logic schemes. In addition, we also have a set of software that uses advanced rendering algorithms to achieve the best image quality.
How much performance improvement can I feel using SLI technology?
How much performance can be improved depends on the application and its scalability. Now the performance of many popular games can be doubled. Generally speaking, applications running with high resolution and high image quality settings have the most obvious performance improvement effect.
What's the difference between this technology and SLI of 3dfx?
NVIDIA SLI is very different from it in many ways. Firstly, 3dfx SLI is implemented on a shared bus based on PCI architecture. The bus throughput of PCI bus is about 100MB/s, while PCI Express is a point-to-point interface, which can provide about 60 times the total bandwidth of PCI bus. Secondly, 3dfx SLI is an analog application for interlaced scanning, and the image quality may be poor due to the difference of digital-to-analog conversion and other factors. In addition, 3dfx Voodoo technology only sets triangles, and geometric operations need CPU to complete, so 3dfx SLI can only improve the performance of simple texture filling rate, which makes use of the flexibility between frames. NVIDIA SLI technology is based on PCI Express technology. It adopts a completely digital frame combination method, which has no influence on the image quality, can improve the geometric performance, supports multiple algorithms to achieve flexibility and scalability, and can choose the most effective method to achieve flexibility and scalability according to application requirements.
Does SLI technology support AGP architecture?
No. SLI technology is specially designed for PCI Express architecture.
How does SLI support PCI Express architecture?
SLI is specially designed for PCI Express architecture. This new bus has a higher bandwidth (two to four times that of AGP 8X), supports synchronous data transmission, and can drive many high-speed graphics processing devices. AGP 8X can only drive one high-speed graphics processing device, so it is not suitable for SLI.
What graphics cards can be included in the SLI configuration?
All GeForce 7800 GTX 5 12, GeForce 7800 GTX, GeForce 7800 GT, GeForce 6800 Ultra, GeForce 6800 GT, GeForce 6800, GeForce 6800 XT, GeForce 6800 LE, GeForce 6600 GT, GeForce 6600 and GeForce 6600 LE graphics cards all support SLI technology.
At present, NVIDIA (Windows XP system) drivers of Quadro also support NVIDIA Quadro FX 4500, Quadro FX 4400, Quadro FX 3450, Quadro FX 3400 and SLI of Quadro FX 1400 boards.
What is the function of SLI connector?
SLI connector is a special connection tool between GPUs, which can transmit synchronization, display and pixel data. SLI connector can make the communication rate between GPUs as high as 1GB/s without occupying the bandwidth of PCI Express bus. SLI connector is suitable for GeForce 6600 GT and later products. For all other SLI-ready graphics cards, the data communication between GPUs is through PCI-Express bus, not through SLI connector. For these mainstream GPUs, PCI-Express bus usually has enough bandwidth to effectively manage extra communication. More powerful GPU(GeForce 6600 gt and later) need SLI connectors to achieve the best scaling effect.
SLI function
What operating systems can SLI technology support?
SLI technology can support 32-bit and 64-bit Windows XP and 32-bit and 64-bit Linux operating systems (IA-32 and AMD-64/EM64T).
What applications can SLI technology support?
SLI can support all game programs, including OpenGL and Direct3D game programs. SLI can use SLI alternate rendering (AFR) or split-screen rendering (SFR) to achieve 3D zoom performance, or it can use SLI anti-aliasing mode to achieve enhanced visual effects. In order to give customers the best "out-of-the-box" experience, NVIDIA has added a set of optimized game settings files that can realize SLI automation. A complete list of these SLI-optimized games can be obtained here. If the application you need doesn't appear in the list, just follow the prompts in the quick instructions to install a new game settings file to activate SLI. Information about workstation applications can be obtained here.
Which driver should I use?
NVIDIA's ForceWare unified driver architecture supports SLI. Just download the latest GeForce or Quadro graphics driver in www.nvidia.com.
NVIDIA constantly adds new drivers to the new SLI application settings file. To support the latest SLI applications, always use the latest drivers.
Before installing new drivers, make sure that you have uninstalled all NVIDIA display drivers from Windows Control Panel. Browse the start menu > Windows control panel > add/remove programs, then search for "NVIDIA drivers" or "NVIDIA display drivers", and then select to delete only NVIDIA display drivers. Restart the computer and install a new driver.
Why are not all games extensible?
After using SLI technology, the performance of applications running on graphics chips can be improved as never before, up to twice as much as before. Today's most popular games and new generation games belong to this category. However, some applications and typical older generation applications are limited by factors other than the processing power of graphics chips.
The most common limitation is CPU-constrained applications. If the application is bound by CPU, enhancing graphics processing ability will not improve performance. At the low resolution of 1024x786, other functions are not turned on, which is the most common situation. Turning on anti-aliasing and anisotropic filters, or switching to a higher resolution, usually brings bottlenecks back to the GPU.
For applications that are greatly affected by CPU performance, NVIDIA provides a new SLI rendering mode, namely SLI antialiasing. This rendering mode enables customers to activate SLI8x or SLI 16x anti-aliasing and enhance the visual effects of all game programs.
What is SLI anti-aliasing technology?
SLI antialiasing technology is a brand-new independent rendering mode. By sharing the anti-aliasing processing task with two graphics cards, the anti-aliasing performance doubles. When enabled, SLI anti-aliasing can provide two new anti-aliasing settings: SLI8x and SLI 16x. In the current driver, you can enable this rendering mode through the following shortcut operations. For more information about SLI antialiasing technology, please visit: (.slizone.com/object/slizone _ sliaa _ howto1_ cn.html).
Does NVIDIA cooperate with developers to study SLI application support?
Yes, NVIDIA is working with developers and training them to make their games benefit from SLI as much as possible. By developing future games through SLI technology, game developers can optimize their games for SLI configuration. In addition, the function of SLI today enables game developers to see the powerful performance of future single GPU systems. In this way, game developers can optimize all aspects of system performance, including CPU utilization. Developers' comments on SLI can be obtained here.
How many monitors can be supported in multi-GPU mode based on SLI technology?
At present, SLI technology can support one monitor in multi-GPU mode. In single GPU mode, users can support up to 4 monitors with the help of NVView multi-monitor technology and Windows XP Dualview technology.
Note: GeForce 6800 Ultra 5 12MB with single graphics card can only support a limited number of widescreen monitors. This is due to the interaction between GPU, application programs and functions that support the improvement of display resolution above the rated resolution.
If the user's system uses Apple's 30-inch monitor or HP's L2035 monitor, NVIDIA recommends that the user configure GeForce 6800 Ultra 5 12MB in single graphics mode.
How to switch from using two or more monitors in 2D/ single GPU mode to using one monitor in SLI mode?
Switch between the two modes by enabling or disabling Multi-GPU Mode (SLI) in the NVIDIA Graphics tab of the Control Panel (right-click the desktop to open the Control Panel). If you use version 80 graphics card driver, you don't need to restart your PC when switching modes.
Does the SLI-based system support output to TV or HDTV?
Support. With the help of the new 80 graphics driver, the SLI system can output signals to standard definition TV and high definition TV, and the highest resolution is 1080i.
What is the green line that appears on my screen in SLI mode?
If a vertical or horizontal green line appears on your screen (displayed here), you have activated display GPU load balancing in NVIDIA display control panel. When this option is activated, it will show how your GPU distributes the image load. For games that use AFR (Alternate Rendering) for rendering, the vertical line will be thicker or thinner according to the total amount of scaling. For games that use SFR (split screen rendering), the horizontal line moves up and down to show how the load is balanced among GPUs. If the top half of the screen is similar to the bottom half, the horizontal line will remain in the middle of the screen.
Note: If Vsynch is also enabled, these lines may not be displayed (this does not mean that SLI mode is not enabled).
Can I overclock with Coolbits and expand the SLI function?
Of course. To enable all SLI functions and overclocking systems, please set Coolbits to1a.
About configuration
Which motherboards can support SLI technology?
So far, only the motherboard equipped with NVIDIA nForce4 SLI MCP has passed the SLI certification. A complete list of motherboards certified by nForce4 SLI can be obtained here. The list will be constantly updated to add new SLI-ready partners.
Which graphics cards can support SLI technology?
SLI is designed for PCI Express, not AGP. The new bus has higher bandwidth (2-4 times that of AGP 8X), supports synchronous data transmission, and has the ability to drive multiple high-speed graphics devices. A complete list of SLI-ready graphics cards can be obtained here. The list will be updated frequently to add new SLI-ready partners.
Is the graphics card compatible?
The current NVIDIA driver cannot support two different brands of graphics cards in SLI mode, and this support function will be added in the new driver. At that time, customers only need to match the GPU mode type. This means that you can use GeForce 6800 Ultra made by XYZ graphics card manufacturer to run GeForce 6800 Ultra made by ABC graphics card manufacturer in SLI mode.
Can factory overclocked graphics cards be mixed with standard graphics cards? ?
Of course. Overclocked GeForce 7800 GTX graphics cards (such as BFG GeForce 7800 GTX OC) can be mixed with standard GeForce 7800 GTX graphics cards.
Can I mix graphics cards with different memory specifications?
Although users are advised not to configure this way, NVIDIA supports users to realize this configuration with the help of Coolbits. When purchasing a second graphics card, users should try to choose a graphics card with the same specifications as the existing graphics card to obtain the best value and performance. For example, if the original graphics card is GeForce 6600 GT 128MB, you'd better buy a new graphics card with GeForce 6600 GT 128MB. However, with Coolbits, users can set both graphics cards to use lower standard video memory and run in SLI mode. Click here to learn how to enable this feature.
Is it necessary to match other graphics card features, such as VIVO?
No need. To configure the SLI system, customers only need to ensure the same NVIDIA GPU (such as GeForce 7800 GTX). As mentioned above, NVIDIA recommends that users use graphics cards with the same memory specifications to ensure the best value and performance.
Can SLI support a PCI Express graphics card and an AGP 8X graphics card? Or PCI Express graphics card and PCI graphics card?
I can't. SLI technology is specially designed for PCI Express architecture.
Can I install only one SLI graphics card on NVIDIA nForce4 SLI motherboard?
Yes, the host based on NVIDIA nForce4 SLI can support any graphics card based on single PCI-Express x 16. Although you don't need two graphics cards, I suggest you use two. For the best experience and upgrade potential, please make sure to use PCI-Express graphics card ready for SLI. Be sure to look for the SLI ready sign.
Where can I buy a SLI connector?
All NVIDIA SLI-ready motherboards and SLI-ready computers are equipped with SLI connectors. If your motherboard supports SLI without connectors, please contact your motherboard manufacturer to obtain connectors.
What power supply does NVIDIA recommend for SLI system?
NVIDIA has extended the SLI-ready certification program to standardize related power configurations. A complete list of SLI-ready power supplies can be obtained here. Generally speaking, according to the requirements of configuration and future updating ability, the power supply has changed greatly. For more information about power supply selection, please click here.
Do the graphics cards of the two GeForce graphics chips use SLI technology?
Yes, there are many graphics cards on the market that integrate NVIDIA SLI technology into one graphics card. Gigabyte's 3D 1 is the first dual-GPU graphics card that has passed the SLI-ready certification. However, this graphics card is only compatible with SLI-ready motherboards in Gigabyte. Be sure to check the SLI certification list before deciding to buy.
Can SLI support more than two graphics cards?
NVIDIA can only support dual GPU expansion at present, but SLI technology is not limited to using only two GPUs.