A while back, I posted a video giving my quick thoughts on the value of SLI. Now that I’ve had the chance to use the setup for a while and dig up some hard numbers for comparison, I want to offer a more in-depth analysis.
Many times, PC gamers like myself will buy a single high-midrange card with the thought that down the road, a second can be added. Dual-card configurations scale very well these days, so if the prices drop significantly on a card it can be more attractive to grab a second one cheap than to try to sell a single one on eBay and splurge on the latest, greatest new card.
And that’s exactly what I did; I bought a single GTX 770 when it was a relatively new card. It was only a modest upgrade from my AMD HD7970, but I actually managed to make about $50 in the trade because stupid people were snatching up AMD cards at a premium for Bitcoin mining. The 770 was more than powerful enough to give me a fantastic gaming experience in 1080p.
Then nVidia released their ‘Maxwell’ cards, the GTX 980 and 970. The former is, frankly, overpriced at somewhere around $600 street. The 970 gives you roughly 85% of the performance of the 980 for around $350 street. I don’t know what nVidia has been thinking with their high-end card pricing lately (Titan for $1000, 780ti for $700), but they certainly know how to make a pair of high-midrange cards more attractive than a single enthusiast-grade card. As of this writing, a single GTX 980 can cost up to $630 for an overclocked version; for just $30 more, you can buy two GTX 970s. nVidia seems determined to make their flagship card a niche product.
There are a couple of caveats with dual-card configurations, though. One is power consumption, although that’s really not a big deal. Putting two cards together does not actually double your power requirement (as one might assume), and you’re talking literally pennies a month to your electric bill. But the bigger issues are scaling and support. The former, these days, tends not to be a problem; dual-card configurations generally scale quite well. This can vary depending on the game and driver though, so it’s possible to have an underwhelming experience if dual-card configurations are not well-supported. In a worse-case scenario, a game won’t support dual-card configurations at all, and you’re left with a second card essentially sitting idle. However, those issues are exceedingly rare. In my experience, modern dual-card gaming works fantastically.
Comparing last year’s ‘performance’ grade cards in SLI to this year’s ‘enthusiast’ grade card
For my GTX 770, it turns out that most games are at least playable at maximum settings in 1440p with a single card. Frame rates generally hover around 30fps in more demanding titles, and anti-aliasing isn’t always viable. But adding a second one gives a great performance boost that allows me to play at buttery-smooth frame rates. Exactly how smooth? Well, I did some digging and could not find any direct comparisons between 770 SLI and a single 980/970. But Anandtech compared a GTX 770 SLI setup to the 780ti, and the former was in most cases faster (it was only slower in games with poor SLI support). Based on their numbers, I looked at their review of the GTX 980, and drew the best comparisons I could. Fortunately, Anandtech tests their games at the same settings and resolutions.
I can still only give a rough estimate of performance, though. One reason is that Anandtech has changed their game suite around, so obviously I can only compare the games that are in both reviews — Metro: Last Light, Grid 2, Crysis 3, Total War: Rome 2, Company of Heroes 2, and Bioshock Infinite. The other reason is that performance has improved regardless due to patches and driver updates. So for example, while the 780ti delivered 59 FPS in Metro: Last Light in its first test, the same card delivered 65 FPS when pitted against the GTX 980. The 770 SLI setup, tested against the then-new 780ti, delivered 61 FPS. It’s reasonable to assume that it could now deliver between 65-70 FPS.
CoH and Rome 2 both have (or had) poor dual-card support, with the latter not tested in SLI in the 980 review (I own Rome 2, but haven’t tried it yet with my SLI setup). So I have to look at what games were tested in both reviews that support dual-card configurations at the time of the review, which leaves me with four games. These are the numbers in rounded FPS, for 1440p:
Crysis 3
GTX 770 SLI = 84
GTX 980 = 61
Grid 2
GTX 770 SLI = 104
GTX 980 = 101
Bioshock Infinite
GTX 770 SLI = 93
GTX 980 = 85
Metro: Last Light
GTX 770 SLI = 62
GTX 980 = 70
Here’s the upside: As I mentioned earlier, I’d wager that diver/game updates in the ten months between reviews would keep the GTX 770 SLI in the lead in Metro: Last Light, and widen their lead in the other games. The performance seems to be, on average, higher than a single GTX 980 — sometimes dramatically so, as in Crysis 3. That’s pretty damn good.
Here’s the downside: I paid a total of $540 for my setup, but a single 980 or 780ti has the advantage of universal game support. A lack of proper support can — as in Rome 2 and CoH2 — hurt the value of the dual-card system. However, keep in mind that this investment was spread out over a long time. There are also people who dropped $700+ on a single 780ti who are now witnessing a $330 card nip at its heels (it’s even worse for the people who spent a grand on a Titan!). It’s just the nature of the PC components that yesterday’s top-end performance is today’s value option.
Is SLI worth it? It depends.
There are basically two strategies with SLI when you’re concerned with performance-per-dollar. One is to buy two cards at once for a high-end setup. This option, I believe, is absolutely worth it. Two 970s, for as little as $30 more than a single 980, will give you some 85% more performance. That’s huge. Given the bizarrely inflated costs of top-end cards and their relatively poor price-to-performance ratio, a pair of high-midrange cards makes for a terrific performance value. It’s true that on rare occasions dual-card setups may not be supported, but in those cases a single high-midrange card will still likely be perfectly playable.
The other strategy — my own — is a bit more dubious. It’s the idea that you can buy a high-midrange card now, because that’s what your budget allows; later, when prices drop and/or you have more cash to spare, you can pick up a second card if you want. Supply plays a big role here. When I bought my second 770, the 980/970s were released but sold out everywhere. It took at least a couple of months for nVidia to get their act together, and 770s were still dropping in price (now, bizarrely, they seem to have gone up in price). And of course, there’s the old “sell it on eBay” strategy. I could have likely sold a single 770 on eBay for around $230; but that’d put me $100-$120 shy of a GTX 970, and the 770 SLI setup is definitely faster. And the only way to really beat the 970 with a single card is to go right to the high end with the 980, as even AMD’s flagship 290X struggles to compete with the 970. So to move to a single high-end card would have set me back considerably more money and, in most cases, still left me with less performance.
Personally, I have no regrets. I love my GTX 770 SLI setup. It works great in 1440p, giving me smooth frame rates and allowing me to play all my games at maximum settings. I’d really like to see some current direct comparisons with the GTX 980, but I have to take what I can get.
This is ultimately why dual-card systems are attractive to me; they present a level of flexibility that you can’t really get from a single card. There are minor drawbacks, to be sure; but in my experience they are rare to the point of being negligible. Scaling, driver support, and performance are all very good with modern dual-card configurations. To me, the value of the SLI setup — whether purchased in one go as an alternative to a single flagship card or drawn out over a year or so as an upgrade option — still surpasses purchasing a single card at the high end.
Anandtech’s reviews:
http://www.anandtech.com/show/7492/the-geforce-gtx-780-ti-review
http://www.anandtech.com/show/8526/nvidia-geforce-gtx-980-review
PC Gaming Are Yes! 