GTX 660 SLI vs GTX 680 - Subjective Comparison
So you have some money to spend on a nice graphics card, and you're wondering if you should go for an SLI setup with two mid-range cards, or buy a single high-end card.
In this case, I'll be subjectively comparing 2x ASUS GTX660 DirectCU II in SLI vs 1x Galaxy GTX680GC.
ASUS Geforce GTX 660 OC DirectCU II - $220 x2 = $440.
Galaxy Geforce GTX 680 GC 2GB - $567 (this model is no longer available. The GTX680GC 4GB is available for $572.55, and the GTX680GC white edition is available for $549.99, but has a different cooler (triple fan vs double fan).
So, it's a valid question. Should somebody who's looking at building or upgrading a mid-high range gaming rig look for 2x smaller cards, or 1x higher end card. There are advantages and disadvantages to both. I have experienced both solutions, and will give my subjective opinion. You can go look at reviews and FPS averages yourself, they're all over the web. This is going to deal more with user experience.
Clearly, 2x GTX660's (custom cooled) are cheaper than 1x GTX680 (custom cooled). By going with the GTX660's, you'll be saving about $120 vs buying the GTX680. Advantage: 2x GTX 660's
If you look at benchmarks, you'll see that the GTX660's in SLI pull slightly ahead of the GTX680. We're not talking much, but about 10-15 frames per second. This is in games that scale SLI well. I play BF3, and I play it on ultra with all the eye candy turned on, at 1920x1200. BF3 scales very well on SLI. I am indeed seeing about 10FPS more with the GTX660's than with the GTX680. This is simply by turning on render.fpsdraw in BF3, and observing the FPS number in the top right hand corner. It is by no means a scientific comparison, but I can confirm that in BF3 at least, the GTX660's do not perform any less than a GTX680. YMMV. Different games scale differently. You may see less performance than a GTX680 in certain games. Advantage: Draw
It is often said that one single large card is better than two smaller cards. Newer games do not always have SLI profiles ready until a couple of weeks after release. Even then, these games may be buggy for a little while until driver issues get resolved (if ever). If you like to play a lot of new releases immediately upon launch, SLI may not be for you. If, however, you're like me, and you play a game for a long time after release, without trying a lot of new titles, then this may not be an issue. For BF3, I have experienced zero compatibility issues. Advantage: GTX680
Newer methods of benchmarking (using frame times vs FPS, and using video capture cards vs FRAPS) are revealing microstuttering (drastically uneven frame times resulting in 'unsmoothness' during gameplay) in a lot of video solutions. The very nature of SLI promotes microstuttering to some degree. Frames are alternatively rendered by each card (the master card and the slave card). Frames rendered by the slave card are sent to the master card, then sent to the display (plugged into the master card). This additional pathway vs a single GPU increases frame latency, potentially resulting in microstuttering. The degree and severity of microstuttering is usually determined by the effectiveness of the graphics drivers. Personally, I have not noticed much microstuttering at all. During most game play (BF3), the illusion of motion appears to be smooth and fluid. There is however, the occasional 'hitch' from time to time. It doesn't happen oftern, (every five minutes or so, if at all), but it is definitely there, whereas with the GTX680 it never happened. Is it enough to affect my gameplay experience? No. Each person is different, however. Somebody else may be able to perceive Microstuttering where I see smooth gameplay. For me, however, Microstuttering is so far not an issue. Advantage: Draw, but leaning towards the GTX680
First let me say that I was blown away by how quiet the GTX660's in SLI are. I by no means have a silent rig. My Coolermaster 690II Advanced is populated by a few Corsair AF fans (both 120 and 140mm), all throttled by the included resistor (to run at slower RPM's), and the H80i in Push/Pull is by no means the quietest AIO in existence. BUT, it is not a LOUD case. It certainly does not sound like a jet plane. More like a constant whisper.
The GTX680GC couldn't be heard over the rest of the rig at idle, but put some load to it, and the fans would ramp up to 40%, and you could definitely hear it over the rest of the rig. It was not what I would call 'loud', but it definitely made a distinguishable noise. Manually increase the fan RPM's to >70%, and the card made a significant 'whooshing' noise.
The GTX660's in SLI, however, cannot be heard at all, even under load. For whatever reason (lower power chip, better heatsink, whatever) the fans don't increase past 20% while under normal game load. These cards are SILENT, and can't be heard over the rest of my rig. Start adjusting the fans manually, and it takes a fan RPM of 60% to even begin to hear these two cards. Set the fans to 100%, and they were no louder than the GTX680 under normal loading (40% fan speed).
Advantage: 2x GTX660's - by a landslide
Cards fail. They don't all fail, but I've had a few cards in need of an RMA in my lifetime. First, let me say that Galaxy has excellent customer service. There is a company rep here on the forum who will help you out with your RMA. That being said, if you ever have to RMA a single card solution, your gaming experience will stop until you have your new card in your rig. With an SLI solution, if one card fails, you still have another one to fall back on. Reduce your game settings accordingly to run on one mid-range card, and keep on playing for the month that it takes to RMA your other card. This is a HUGE plus. Advantage: 2x GTX660's
So, what should you buy? 2 smaller cards in SLI, or one larger single card? Well, that depends. If you like to play a lot of brand new titles, or can perceive microstuttering, then definitely go for the single larger card (like a GTX670 or a GTX680). If, however, you're like me, and you continue playing titles for a long time after release, and can't perceive any microstuttering, then you may very well be better off with two smaller cards in SLI. You stand a good chance of saving money, have a potentially quieter rig (although it all depends on the cooling solution for your specific cards) and you have redundancy in case of failure.
I know that I'm happier with my 2xGTX660's than my single GTX680. YMMV.
Good article! For me the micro stuttering in SLI is very noticable. The same framerate in a single gpu feels a lot smoother to me that it does in SLI.
Nice write up. I haven't had a high end card in years and have never gone SLI/XFire, but I think you have hit the nail on the head with your comments about game use. Those that jump at new games on release day and jump from game to game are going to be playing it safe by going to a single high end card. If you buy a game after its been on the market for even a month, hang on to it for a while, etc, SLI is likely going to be a more viable option. The only real issue I can see with SLI/Xfire, is those select few games that may never get proper driver optimizations. You are pretty much going to have to skip those choices, or revert to a single card.
Personally I would still treat SLI or Xfire as an upgrade option more than an initial path (there is, however, a time an place for everything). One other consideration is that with SLI 660 when it comes time to upgrade you will need to sell both cards and buy new cards. With the 680, you have the option of adding a second down the road.
Nice work, go triple if you want to eliminate stutter.
Additionally, the reason these cards are so quiet, is because of the spacing of the video cards. There are three slots separating the 2 populated PCI-E slots. Therefore there is an entire empty slot separating heatsink of the top card from the PCB of the bottom card. This allows lots of airflow and reduces card temps/fan speeds to the point where they're silent.
Add a third card, and the heatsink of the middle card would only be separated from the PCB of the bottom card by a few millimeters, potentially increasing heat production, and noise.
Part of the reason this works over a single GTX680 is because this particular SLI solution is so quiet in comparison.
^^^^ I've never experience "micro-stutter" in any of my multi GPU solutions....sorry guys. Just wicked killer gameplay, if your experiencing serious micro stutter in your multi card (nv) solution, check your other Hardware, something isnt right ;)....or try a clean install of latest Drivers.
Also, I havent come across a single game that I havent been able to run in SLi, if a Driver isnt available for a new title, you can always jump the gun and create a SLi Profile, although with nv the new SLi capable Driver will usually be released vry very soon if not the same day as a game release.....still a lot of "myths" with SLi I see....just sayin.
Great job woth the Review above :)
RJ, SLI microstutter is there and measurable, and it has been measured and graphed. Some people don't notice it. You are one of them.
RJBarker, count yourself among the lucky ones that you cannot see Microstuttering. It allows us so many more options with regards to our video solutions.
RJ we are in the same boat this time, Only once have I seen Microstutter and it was with a Crossfire setup and only with one game, Starwars MMO that crapy new one haha. But other than that I have found SLI and Crossfire to be damn nice these days, Also and I have tested this on a few games in Crossfire your load times go way way down between levels or areas in games. I will try to find time to do a write up about this when I get a chance :)
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