Are nVidia's SLI Cards Worth the Investment?

aendeuryu asks: "So there's a lot of buzz right now about nVidia's SLI architecture, which allows for two video cards to be placed in tandem PCI-express sockets on the same motherboard to share processing. Based on the relatively low price of a PCIx 6600GT, and the promise of it dipping further, it would seem like a good idea to invest in one and an appropriate motherboard, so that one can upgrade later, right? So, for anybody who's actually got the setup at home, have SLI cards shown themselves to be worth the investment?" "There are two problems with the current state of SLI:

• It's hard to tell what software companies plan to take advantage of the SLI architecture when coding their games -- Doom3 and Several Benchmark software tests show a significant improvement over non-SLI setups, whereas some games like Far Cry actually show a performance hit over single video-card setups.
  
  
• At the moment, the upgrade path actually requires two identical cards, so you'd have to choose your initial purchase extra carefully to make sure your model is still around when it's time to upgrade.

What does the future hold for SLI, or, for that matter, the ATI counterpart, AMR?"

Comments

Far Cry Performance

[he1icine]

Far Cry performance *IS* improved with SLI as long as you are running above 1024x768 so says Anandtech:

http://www.anandtech.com/video/showdoc.aspx?i=2284 &p=14

and if you are going to drop $800-1200 on video cards, you are not likely to still be gaming at 1024x768, but your credit card might be weeping.

Re:I think it;s worth it and the idea is great.

[psergiu]

There are A LOT of cards with 2 (or even 3) outputs on the market now. You don't need 2 cards. And /even/ if you decide to put 2 cards (that support SLI) in your PC, you will have to REMOVE the SLI cable to get 2 outputs :)

Investment?

[lezerno]

How do you define investment? Get the system you need to use today. Buying computer equipment for future use is a bad "investment". By the time you want to upgrade the card the rest of the system will be outdated.

Short Answer: Go with a single 6800GT/Ultra

[JFitzsimmons]

NVIDIA's SLI Shortchanges Gamers?

A nice article.

In my opinion? No.

[Dragoon412]

SLI is apparently aimed at the same market as the Pentium 4 Extreme Edition, and the Athlon 64 FX - namely, the crowd who views their synthetic benchmark scores as a sort of virtual penis. ...and the exceedingly small market of people that can build PCs without any budget limitations.

The current crop of video cards is hideously expensive. Where the last generation's flagship models weighed in around $500 at retail (the 9800 XT and 5950 Ultra), this new batch has seen the X850 XT Plantinum Edition retailing for $700 and the 6800 Ultra going for not much less. The "average" performers for this generation are in the high $200-$300 range.

Furthermore, SLI is a lot like SMP. First off, the game needs to actually be able to take advantage of it. Next, even if the game does, you're not seeing a linear performance boost; that is to say, if you've got a pair of 6800 Ultras, you're not going to see double performance. The rule of thumb is it'll boost performance by about 65% - sure, it's very substantial, but with the premium price on cards already, it's an even less worthwhile purpose. To top it off, you're going to be looking at an extra $50 or so on a motherboard with SLI, and who knows how much extra in cooling.

So, from a performance standpoint, SLI is obviously the king, but from a cost effectiveness standpoint, it's about as bad as it gets.

As for using SLI to level the performance field with mid-range and low-range cards, buying an SLI board with a pair of 6600GTs is going to run you, say, $600 ($200 for a mainboard, $200 for each card). That may actually be worth it, as you're going to drop the same amount of money on a 6800 GT & similar non-SLI board which will perform slightly worse.

But then, here's the problem with that: not only do games need to support SLI, but nVidia needs to write their drivers to support a specific game. Play a game that flies under nVidia's radar? Too bad, no SLI for you. Additionally, while a pair of 6600GTs perform marginally better than a single 6800GT right now, what's to say there'll be a great price point on this type of card for the next generation when you go to upgrade?

SLI's close to being worthwhile, but at the moment, I'd not bother with it. Maybe once the technology's more mature.

Correction

[NRP128]

At the moment, the upgrade path actually requires two identical cards, so you'd have to choose your initial purchase extra carefully to make sure your model is still around when it's time to upgrade.

Actually you don't need identical boards, they have to be identical chipsets. You can mix and match vendors, so long as the chips and configs are the same. You can't run a 6600 and a 6600GT in SLI mode, but you COULD (in theory) run them to power 4 DVI displays. I say in theory because everyone is still so hung up on SLI i haven't seen anybody try this yet. The main outline of the spec is that you can run cards from different vendors, they just have to be the same configs. Many of you know that already, but i felt obligated to clarify for those who haven't been keeping up ;)

Personally i'm looking at SLI capable boards for my next mobo upgrade for that reason above, not for the SLI portion, but the fact that i may be able to run dual vid cards and not have one on the slow ass PCI bus. With most integrated mobo periphials moving to PCIe anyway, this isn't so much an issue, but if you have firewire, any kind of hdd access, audio, etc moving on the 133MB/s PCI bus you're going to be hearing pops and skips in your audio, looking for lost packets, and pulling your hair out with IRQ conflicts. I don't want to add video to the mess that already exists. dual PCIe x16 slots seem a VERY nice solution :)