How does 2 graphic cards work?

[Zultir]

I may not be the techiest guy out there but i do know a few things about computers :P

So was thinking and a question came accross my mind, and that question was, how do 2 GPUs in one computer work when only one is hooked to the display.

Also on a side note i have an OCed GTX 560 Ti in my computer, was wondering if getting a second one would help any in top, high end games, like crysis 2 on best settings, or some other game :P

That will be all, thank you :3

[Rowrin]

I believe most graphics cards have something called an SLI bridge that you connect, after both are installed on the mobo, which will like the two together.

Haven't read up on it on a while but you can just google "how do SLI graphics cards work" and probably come up with something.

[sadistlex]

Well actually when you connect 2 GPUs you have to connect them together with a special wire. And of course getting a second GPU will boost performance. The game has to support SLI/Crossfire though. I am pretty sure most of high end games support it.

[OhpUldum]

Two video cards running through SLi or XFire use a bridge that connects the two cards. This bridge allows any information being processed to be dealt with by both GPU's if necessary.

We would need to know the rest of your system specs before giving you advice to pick up a second GTX 560. However in most cases a second video card will give you a performance increase.

[Deleted]

You need a motherboard with two PCI-e lanes both running at 8x @ dual mode. And you need a motherboard with either SLI (For nvidia cards) Or CrossFire (for AMD cards)
You connect the 2 cards with a bridge (google sli bridge). Then if the game or program supports SLI or CF. The 2 cards will work together.

[Zultir]

You need a motherboard with two PCI-e lanes both running at 8x @ dual mode. And you need a motherboard with either SLI (For nvidia cards) Or CrossFire (for AMD cards)
You connect the 2 cards with a bridge (google sli bridge). Then if the game or program supports SLI or CF. The 2 cards will work together.

what is the game does not support SLI / CF? would just the main GPU be functioning?

Also do you need certain type of MB that support this? My MB does have 2 PCI-E slots

[Parrin]

"SLI allows two or more graphics processing units (GPUs) to share the workload when rendering a 3D scene. Ideally, two identical graphics cards are installed in a motherboard that contains two PCI-Express x16 slots, set up in a master-slave configuration. Both cards are given the same part of the 3D scene to render, but effectively half of the work load is sent to the slave card through a connector called the SLI Bridge. As an example, the master card works on the top half of the scene while the slave card works on the bottom half. When the slave card is done, it sends its output to the master card, which combines the two images to form one and then outputs the final render to the monitor."

This is from the wikipedia article on SLI, which requires a SLI bridge. Radeon cards, which usually combine through a Crossfire bridge, allow a less powerful option without the bridge. But for either to get the best results, you will want to utilize the bridge, or connector.

[OhpUldum]

Certain motherboards will support SLi and Xfire or just one or the other. Without knowing your motherboard model we can't tell you if you have support. In games that do not support SLi/Xfire the game just uses the one GPU automatically.

[Zultir]

Also some specs:

Ram: 8GB (2 x 4GB) DDR3
PSU: 730w
CPU: i5 2500K 3.7 GHz
MB: LGA 1155 Intel P67 SATA 6Gb/s USB 3.0 ATX
GPU: OCed GTX 560 Ti
I think thats it...

Also im running Win7 64

On a 1900 x 1080 monitor



P.s. I can't post links yet so if you want to see my MB go to newegg and type "GA-P67A-D3-B3" in the search, it will pop up

[OhpUldum]

Well your motherboard can support a second video at X4 speed and your power supply without knowing a model is hard to say. If it is a shitty model / manufacturer then no I wouldn't suggest it but should it be a known proven brand then that should be adequate for a dual GTX560.

[Zultir]

Well your motherboard can support a second video at X4 speed and your power supply without knowing a model is hard to say. If it is a shitty model / manufacturer then no I wouldn't suggest it but should it be a known proven brand then that should be adequate for a dual GTX560.

newegg . com/Product/Product.aspx?Item=N82E16817152036
^^PSU

Also x4 speed bad? os am i just not getting as big as a buff to my preformance as i would if it were x8? That big of a difference?

[Skelly]

Your PSU does not have enough 6-pin PCI-E connectors to connect another 560 Ti.

[dariok]

Also some specs:

Ram: 8GB (2 x 4GB) DDR3
PSU: 730w
CPU: i5 2500K 3.7 GHz
MB: LGA 1155 Intel P67 SATA 6Gb/s USB 3.0 ATX
GPU: OCed GTX 560 Ti
I think thats it...

Also im running Win7 64

On a 1900 x 1080 monitor



P.s. I can't post links yet so if you want to see my MB go to newegg and type "GA-P67A-D3-B3" in the search, it will pop up

I really don't know where some people are getting information from...
Anyway, some facts:

1. Your current hardware fully supports SLi configuration at full speeds. ( I do not know manufacturer of your PSU but quick search shows that there are no 730W PSUs that do not have 2 6pin connectors for dual gfx. Also 2x 560Ti draw close to 300W under full load, rest of your system should not be over 150W unless you are doing some fancy overclocking. )

2. The performance boost will be negligible in some games and visible in others, we should really know what games you like to play. Crysis 2 should see you a ~20% increase in fps at 1080p, this is just a rough estimate based on tests of similar configurations. **estimate of 20% is based on lowest score I have seen, some report up to 50% increase of minimum fps