How to trick out your gaming PC with multiple graphics cards

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Using onboard graphics together with a separate graphics card

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 · In order to use the onboard graphics and 2 video cards, your computer needs to support or have the Switchable Graphics feature. The Switchable Graphics allows you to switch between using the Intel graphics and a discrete graphics controller in a computer.

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Warnings

  • Make sure to research before messing around with your computer. Make sure you know what you are doing. Get familiar with the safety rules so you don’t hurt yourself or break your computer.

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Before you install

Before installing a secondary video card, we recommend you review the below checklist first to help prevent possible issues in the future.

Setting up your own Crossfire and SLI systems

Assuming you have plenty of cooling, a compatible motherboard, and a power supply powerful enough to power the extra graphics cards, installing those cards in a system for SLI or CrossFire is relatively straightforward; the process isn’t much different than installing a single graphics card.

Begin by shutting down the system and unplugging it from the electrical outlet. Next, insert the graphics cards into the requisite PCI Express x16 slots on the motherboard and connect the necessary supplemental 6- or 8-pin power feeds for your particular cards. Then install the SLI or CrossFire bridge connector (or connectors) to link the cards together.

With the exception of a few low-end products, Nvidia GeForce and AMD Radeon graphics cards running in multi-GPU configurations require a bridge connector to link the cards together. For more than two graphics cards, you must use larger 3-way or 4-way bridges, or multiple single bridges.

Once everything is properly seated and secured, connect your monitor (or monitors) to the primary graphics card—typically the card in the PCI Express x16 slot closest to the processor on the motherboard. Then power up the system, let your operating system boot, and install the latest drivers for the graphics cards.

After you install the necessary hardware and drivers, you must enable CrossFire and SLI in your graphics control panel. You can find CrossFire settings in the “AMD CrossFireX” section (above) under Performance in the Catalyst Control Center, and SLI settings in the “Configure SLI, Surround, PhysX” section (below) of Nvidia’s GeForce drives.

After installing the graphics drivers, you may receive a notification that the system is SLI- or CrossFire-capable and be prompted to enable the feature. If not, simply open your graphics control by right-clicking on a blank section of your desktop and selecting either ‘Catalyst Control Center’ for AMD Radeon cards or ‘Nvidia Control Panel’ for GeForce cards from the menu, then navigate to the necessary menu to enable CrossFire or SLI. Find SLI-related settings can be found in the “Configure SLI, Surround, PhysX” section of Nvidia’s GeForce drives, and CrossFire settings in the “AMD CrossFireX” menu in the Performance section of the Catalyst Control Center.

Disadvantages

The primary disadvantage of running dual graphics cards is the cost. Top-of-the-line cards can cost $500 or more. While both ATI and Nvidia offer lower-priced cards with dual capability, you can spend the same amount of money for a single card with equal or better performance than two low-priced GPUs.

Another disadvantage is that not all games benefit from multiple graphics cards and some graphics engines do not handle two cards well. Some games may show a decrease in performance over a single graphics card setup. In some cases, stuttering makes the video game look choppy.

Graphics cards are power-hungry. Two graphics cards installed in a computer can double the amount of power required to run them in tandem. For example, a single high-end graphics card might require a 500-watt power supply to function properly; two of these cards may require 850 watts. Most consumer desktops aren’t equipped with high-wattage power supplies. Refer to the computer power supply wattage and requirements to determine if your system can run dual graphics cards.

The performance benefits of a dual-card environment vary depending on the other components in the computer system. Even with two of the highest level graphics cards, a low-end processor can throttle the amount of data the system provides to the graphics cards. Dual graphics cards are typically recommended only in high-end systems.

People who mine cryptocurrency often run massive banks of video cards because GPUs process blockchain transactions much more efficiently than a CPU.

GPU Affinity [ edit]

GPU affinity binds a single instance of TouchDesigner (one process) to a single GPU. With multiple GPUs in the system you can have multiple instances of TouchDesigner, each bound to a unique GPU. This avoids any GPU->GPU communication and puts multiple GPUs to work. One process could be using it’s 2 outputs to send data to projectors, while the 2nd GPU is connected to monitors you are using to run a 2nd TouchDesigner process that is controlling the show (sending commands and data streams to the first instance via the various networking OPs).

It is also a good solution if you are having Horizontal Tearing by avoiding connecting outputs with different resolution/refresh rate (EDIDs) to the same graphics card.

When using GPU Affinity, make sure that the windows from the TouchDesigner process which is bound to a particular GPU do not overlap onto the desktop space of the other GPU(s). If windows are shown on the wrong GPUs it will cause the data to get copied between GPUs which is what we are trying to avoid by using GPU affinity. This is acceptable for creating and editing your files, but during performance playback you should keep the windows only on monitors connected to the GPU that the process is bound to.

GPU Affinity is supported by Nvidia Quadro GPUs, and all modern AMD GPUs.

Affinity Usage [ edit]

GPU Affinity is used by using the -gpuformonitor command line option when launching TouchDesigner. This command binds the process to the GPU connected to the specified monitor. The monitors are indexed the same way they are in the Monitors DAT, which is left to right and bottom to top. You can specify any monitor that is connected to the particular GPU you want to bind to. For example if you only want run two instances of TouchDesigner, each running on the first and second graphic card respectively, and each GPU has only 1 monitor connected, you’d launch them with a .bat file like this:

To see if the binding is working as you expected, use the Monitors DAT and look at the ‘affinity’ column.

Geforce Cards [ edit]

GPU Affinity is not supported on Geforce level cards. It is not recommended that you use multiple Geforce cards in a single system. In Windows 7 or later all the work will get done by the fastest GPU and then final images will be copied to the other GPUs to be displayed on-screen. However the performance of this vs. Quadros is unknown. Even on Quadro’s working without GPU affinity is not a suggested way to work.

We can not offer support for graphics issues caused by using multiple Geforce cards in a single system.

Do you sell any items you mentioned on your reference for How To Use Multiple Graphics Cards?

Of course not, we offer our suggestions, tips,… only, and we don’t sell or exchange any items on our site. You can refer to the Amazon site to buy the items we mentioned.

Choose a driver

The problem with multiple monitors is that often you’re asking applications to work in an environment they were never designed for, and aren’t expecting. That’s besides trying to physically align multiple bulky displays next to each other.

Nvidia and AMD provide tools within their display drivers to help correct for the displays’ bezels, which helps reduce the jarring effect of moving between displays. Part of the drive here is that both manufacturers are pushing triple-screen gaming as a key use for their high-end gaming cards.

With a total screen resolution of 5,760 x 1,080, you can imagine why you’ll need a high-end card to make the most of those IMAX-like displays. The support of Nvidia and AMD is vital, and provides reassurance that multi-monitor setups can be made to work well.

Going beyond three screens, the AMD Eyefinity system helps make multiple displays ‘invisible’ to applications by enabling you to group multiple monitors into a seemingly single display. These features are on top of what Windows offers already, and do a fine job of handling as many monitors as you can throw at them.

Desktop control

Use the tools provided for a better life

1. Windows controls

Windows provides some useful controls for your many displays. At their most basic, they enable you to mimic how the displays line up physically. The idea is that the cursor lines up as you move it from one display to another. The orientation controls enable you to deal with displays that are rotated or upside down, but that’s as far as it goes.

2. ATI HydraVision

ATI has always tried to provide ways to control multiple desktops, multiple screens and applications via HydraVision. This started life as a separate tool, but now lives inside the driver itself alongside the Desktop Management. It shouldn’t be overlooked, as it provides some powerful tools. It supports multiple desktops, and will remember application positions to snap windows to its grid and provide better controls.

3. Nvidia controls

The driver for Geforce cards seems to be the weakest in multi-monitor setups, and tends to ignore others on the system. Perhaps the developers saw no need for such controls when they’re already built into Windows. To enable Surround Gaming you’ll need to follow the Configure Displays guide within the 3D settings on the Nvidia driver. This will explain which outputs can be used depending on the attached cards.

Multiple GPUs used as-is [ edit]

Without GPU Affinity/SLI Mosaic all the work for processes get sent to the fastest GPU, and only the final images are sent across to the other GPUs to get displayed on-screen. This is similar to SLI Mosaic/EyeFinity, but the driver is set up in a less optimal mode. This way of working can have a large performance impact on your project and is not yet recommended, but may be appropriate in certain situations.

See also Multiple Monitors

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