SLI Stands for Silly

If you haven’t yet placed your order for your 7800 GTX cards (I am assuming that you are buying a pair), here are some reasons you might want to wait. I realize that this advice flies in the face of all that is holy here at Tom’s Hardware, where we celebrate the new, the sexy, the champions of performance and the twin lords of graphics horsepower.

Before you buy, you might want to check and see what you are going to actually pay for the set : in our early research, we estimate that $1600 a pair is the starting price with many resellers.

Yes, the 7800 is faster than the 6800, and even faster than the reigning ATI champion, the X850. And yes, two mints are better than one : we found that the paired SLI set delivered on its performance claims, getting somewhere around 25 percent performance gains for certain situations.

But if you are thinking about spending at least $1600, and probably closer to $2000 on a graphics system by the time the market bids up the prices on these cards, then you are dreaming. Forget about where the ultimate price point on these cards will end up. That is just the beginning of your upgrade path. You probably are going to need a new motherboard that supports SLI so you might as well start that upgrade.

And you probably are going to want to buy at least one new monitor, and probably two. The dual card system only runs DVI connectors, so if you have stuck in the analog VGA era then you might as well bite that bullet. Why two ? Well, these days you can get good two-for-one deals and besides, each card comes with dual DVI connectors so you might as well get the extra screen real estate for all those times that you aren’t going to be playing games and want to use that fancy new card for something productive.

Yes, that is the dirty secret that no one is really getting into any detail. While the 7800 is blazingly fast, and the graphics are super-sharp and oh-so wonderful to look at, they only deliver the goods for the latest generation of games, and a very limited number at that. This is because, like any new technology, you need the underlying software to support its new features.

At the press briefing, Nvidia posted a slide with its results that showed many games would get at least a 20% increase in performance when the 7800 dual SLI solution was compared to the 6800 Ultra SLI set. This is about where our own tests ended up, depending on the particular screen resolution and other configuration settings we used. According to Nvidia, racing games like Need 4 Speed and TOCA Race driver got even larger increments in performance. We haven’t tested those yet.

The other unmentionable fact, and here is where I am sure to draw a few readers ire, is that all of these performance gains is nothing compared to what you can do on the cards if you drop your resolution a notch or two. Granted, the whole point in getting these puppies is to have beautifully crisp graphics. But if you are just concerned for speed, you already know that 1600x1200 isn’t going to be the fastest mode your game operates in.

What these cards make possible is that you can run in hi res and still get reasonably solid performance, if your game is designed to take advantage of all the parallel pipes that are programmed into the 7800. Take a look at the following chart, which compares the percentage improvement in frame rates for Doom 3 that we saw when we compared the 7800, the 6800, and the ATI 850 cards.

You’ll notice that the performance edge for the 7800 increases for the higher resolution configurations. The single 7800 system bested the ATI card anywhere from 8 to 51 percent, and the single 7800 beat the single 6800 card anywhere from 6 to 27 %.

So why wait ? Several reasons. We all know that ATI has something to deliver soon and chances are it will best the 7800 in at least a few areas. You might want to wait until the initial feeding frenzy and midnight madness subsides and prices return to reasonable levels, or at least within striking distance of the MSRP. Waiting also might help increase the actual number of applications that will support the parallel pipes on the 7800, and maybe we’ll see a few business-oriented apps join in as well. And you might want to let the motherboard makers get all the kinks out of their BIOS and firmware support for SLI, which vexed our staff in our initial tests (especially on some of the newer dual-core Intel boards as our stress test series has documented).

But don’t listen to me. Place your order now, and let’s see how high the market will go on these babies. Maybe I should look into a 7800 futures market.

Best

David Strom
Editor-in-chief
Tom’s Hardware