GeForce GTX 280 SLI Dual | Triple review test - 2 - SLI explained and Installation

Dear Guru - Whot is zet SLI mode you tolk aboot ?

Is there anyone on this website who doesn't know that SLI & Crossfire is ? Damm it .. I see a couple of fingers in the back.

Okay so, just like ATi's Crossfire, NVIDIA SLI is a situation where you add a second similar generation graphics card (or in more GPUs) to the one you already have in your PC and effectively try to double, triple or even quadruple your raw rendering gaming performance. Today for example we place two NVIDIA graphics cards into a SLI compatible mainboard. We bridge them together, install drivers after which most games can take advantage of the extra horsepower we just added into the system.

The idea is not new at all ... if you are familiar with the hardware developments over the past couple of years you'll remember that 3dfx had a very familiar concept with the Voodoo 2 graphics cards series. There are multiple ways to manage two cards rendering one frame; think of Supertiling, it's a popular form of rendering. Alternate frame Rendering, each card will render a frame (even/uneven) or Split Frame rendering, simply one GPU renders the upper or the lower part of the frame. So you see there are many methods where two or more GPUs can be utilized to bring you a substantial gain in performance.

This review will show SLI performance results throughout the benchmark sessions based on two GPUs rendering the game, and later on in the article even three GPUs rending your games.

Gettin' down to business - How to setup SLI

Typically I want articles as this one to be some sort of small do-it-yourself guide, so let's talk a little about installation. That way you can replicate the situation at hand at home.

First off we are dealing with really high-end gear today. I do recommend you to have two x16 PCIe slots on your NVIDIA nForce mainboard. Our test will be conducted on a nForce 680i SLI mainboard, which most of you guys have.

We insert the two cards into the upper and lower x16 PCIe slot.

Now it's a question of connecting the power supply connectors. And that sounds more simple than it really is. Recommended is a PSU of, at the very least, 750-800 Watts. It's not that your PC will consume that much power, it's just that you want to make sure your PSU can deal with the hefty load and will stay stable during you entire gaming experience.

Make note of the fact that for two GeForce GTX 280 cards you'll need the PSU to be able to supply 2x 6-pin and 2x 8-pin PCIe graphics connectors. Today w used the BFG 800Watt ES PSU (read review); perfectly stable, life-time warranty and it already has these connectors on board. So no need for nasty looking splitter cables etc.

My rule for a good PSU in this class of gaming: GeForce GTX 280 SLI requires you to have a 800 Watt power supply unit at minimum if you use it in a high-end system. That power supply needs to have (in total accumulated) at least 55 Amps available on the 12 volts rails.

When you go nuts with 3way SLI, seriously a kilowatt or 1200 Watt PSU is my recommendation. For Triple SLI we used an Enermax Galaxy 1000 Watt PSU (review here), which was perfectly stable including a massive system overclock. 75 AMPs here on the 12 volts rail is nothing to be ashamed about.

Here you can see the SLI (2-way) bridge applied.

Once you connected the power cables, you need to apply the SLI bridge (visible in the middle left of the photo) that you should have received with your mainboard. There are actually two SLI fingers on each card, it doesn't matter which one you use. That second SLI finger is only used in combo with three-way SLI. 

Example of the 3-way SLI bridge being applied

Once you have your system ready you can have SLI powered up and ready to roll within a minute, as it really is that easy to do. Now you just need to install the latest drivers, give her a reboot and you are good to go.

it's alive .. IT'S ALIVE !