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SLI Primer

Posted by Hemos on from the wave-of-the-future dept.

GFXguy writes "If you are looking to catch up on some hardware learning you may want to check out "SL Why?". It is a short article that goes over the basics of SLI graphics. The article goes over some strengths and weaknesses of this technology as well. It looks like one video card is not going to cut it any more, at least for the hardcore gamers out there. "

1 of 275 comments (clear)

  1. FUD Biased Article with Inaccuracies by dbretton · · Score: 4, Insightful

    #1) Doom 3 runs in SFR mode, not AFR.

    #2) CPU issue is overblown. I'm not even sure if any additional information is truly sent to the processor.
    In AFR, the data for each frame is sent to alternating graphics cards. Since the frames would have been processed anyway, there is not any additional load on the CPU than there would be for an identical system with a video card that is twice as powerful as in an SLI system.
    In SFR, the same data is sent to two graphics cards. This would be more data, but seemingly require only a smidgen more CPU power. The video cards send the data between each other over a dedicated bridge, and the video cards handle the task of reassembling the image into a single frame.

    #3) SLI card cost. 6600GT AGP cards cost more than their PCIe counterpart. 6800 AGP cards cost less. This has more to do with the amount of time in the market than anything else. In 3 months, the prices will be equal.

    #4) Stability. "...certain older cards that are said to be SLI compatible have serious stability problems when used with SLI, but, for example, not all 6800 GT cards can be used with SLI". To date, I have not seen a PCIe 6600GT or 6800GT card released which is not SLI compatible. Not all 6800GT cards can be used with SLI, but that has more to do with the fact that many cards are AGP based and older than two months (when the first SLI motherboards were released).

    #5) No benefit. "From what I heard, more than a few games realize no FPS gains at all from the addition of a second video card". First, this is rumor. Many games realize no benefit at low resolutions (640x480, some at 800x600) because the games are more CPU bound than video card bound. All the games that are SLI compatible definitely realize solid FPS gains. Moreover, those gains can be "converted" into graphics enhancements (i.e. no need to go from 60fps to 95 fps, but now you can turn on 8xAA or up the screen resolution, etc.)

    #6) Dual GPU cards. The author obviously doesn't know what he's talking about here. The Gigabyte dual GPU card is just an SLI solution on a single graphics card. It's (almost) exactly the same as having 2x6600GT cards. It uses the same technology and produces the same results. So what's this viable new technology on the horizon he is talking about?

    #7) SLI cannot be forced. Of course it can! The default mode is "no SLI". This can be changed in the configuration options for the card.