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Frame Rating Dissected: Full Details on Capture-based Graphics Performance Testing

DiRT 3 – HD 7970 versus GTX 680

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Dirt 3 is a game that is already running at very high frame rates at 1920x1080 so it comes as no surprise that the scaling in CrossFire and SLI is minimal.  In terms of single GPU performance though the HD 7970 stays ahead of the GXT 680 consistently.

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This is an interesting plot; while the green and black lines both are pretty thin and tight indicating a solid gaming experience with little stutter or frame variance, both the blue and orange lines of the multi-GPU configs have higher than expected variance.  What might be more interesting is that this is the first time thus far that we haven’t found the HD 7970s in CrossFire to be completely abysmal. 

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Well look at that!  Both the observed and FRAPS FPS graphs are nearly the same, telling us that while AMD has some definite CrossFire scaling issues with Battlefield 3 and Crysis 3, DiRT 3 doesn’t appear to have suffering from the same ailment. 

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The minimum frame rate percentile graph shows us that the HD 7970 is indeed faster than the GTX 680 across the board, though both cards are overpowered for this game at 19x10.  CrossFire and SLI both stay in range of each other the entire time as well with SLI falling a bit behind after the 84th percentile.

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Our ISU graph here shows an interesting result and different view of performance than the minimum FPS percentile graph above it.  While the two cards were close in comparison before the HD 7970s in CrossFire actually look much better than SLI in this case, indicating a “tighter” band of frame times. 

 

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The results are starting out the same here at 2560x1440 though there is much more scaling occurring on both AMD and NVIDIA setups by adding a second card.

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Hmm, that’s interesting.  This was an occurrence we saw nearly every run of Dirt 3 with CrossFire at 25x14 so I wanted to be sure to include it here.  At the times between 25 and 30 seconds (it was different times in each run) we saw runts pop up again, almost as if the CrossFire cards were “getting out of phase” or something like that.  SLI has a few bigger spikes but nothing ever showed up that consistently. 

As a tip to one of my concluding thoughts of this article, I think that this result, and others we’ll show before the end, is indicative of the major problem for CrossFire.  It appears that when the GPU is the primary bottleneck, CrossFire just can’t keep up in some way and produces runts.  That would explain why would see it at 25x14 here but NOT at 19x12.  Just keep that in mind as you keep reading.

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As a result of that series of runts, the observed FPS of HD 7970s in CrossFire drops during that time.

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The minimum FPS percentiles graph shows the same result in a different way – it is obvious that the runts are causing the frame rates at the back 5% of this chart and the “build up” to and away from that subsection are what causes the decline around the 85% mark.

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The frame variance and potential stutter graph here shows the results of that spike of runts as well with a much higher overall variance than SLI or either single card.

 

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Dirt 3 was another game case where 5760x1080 results didn’t pan out for the HD 7970 in CrossFire so we are only seeing single GPUs and SLI results.  SLI is scaling very well but the single GTX 680 is getting bested by the HD 7970 the entire time.

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All of our results are pretty good here the GTX 680s in SLI produce a fairly tight frame time line and frame rates well above either single card.

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Without any runts or drops our observed frame rates are identical to our FRAPS frame rates.

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Tight plots of frame times indicate and nearly straight lines here match our real-world game play experiences of smooth frame rates.

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While this might look bad for the cards in question – check the scale on the left!  The most frame time variance we see on any option here is 1.6ms so we come away from our testing happy with 5760x1080 results for everything but the HD 7970s in CrossFire.

March 30, 2013 | 08:47 PM - Posted by bystander (not verified)

I have a hard time trying to grasp exactly how erratic input would affect the results. I have a feeling, based on my constitution (I get simulator sickness with poor latency), that the best case is which ever has the lowest worst case interval times.

March 31, 2013 | 01:55 AM - Posted by bystander (not verified)

..But then you have occasional latency increases. Of course those increases are to remove redundant frames, and once increased, they probably don't need much adjustments most the time.

This whole topic always gets me going back and forth, but my instincts is overall, even if latency is considered, even spacing matters more as it adds more useful points of input, assuming it adds only marginal/occasional increases of latency.

March 28, 2013 | 08:20 PM - Posted by Bob Jones (not verified)

Can you address the visual quality differences between the two cards? Specifically on Sleeping Dogs, the 660 Ti seems to be missing some lighting sources outside - most noticeable is the cafe/shop lights before you go down the stairs, and then the store across the street right at the end of the vieo.

March 29, 2013 | 10:46 AM - Posted by Ryan Shrout

Time of day in the game when those videos were recorded?  They should be basically identical, I'll check.

March 29, 2013 | 03:10 AM - Posted by I don't have a name. (not verified)

Fascinating article. I think it'll take a few reads to fully comprehend everything that is being said. Thank you indeed, I found it fascinating. Certainly, as a 7970 owner, I'll be holding off on a potential second 7970 purchase for the time being.

March 29, 2013 | 05:09 AM - Posted by rezes (not verified)

The last GeForce 314.22 Beta Drivers and last Radeon drivers 13.3 beta 3. Please using these drivers on yours test.

AMD driver may be more stable on this drivers!

March 29, 2013 | 10:46 AM - Posted by Ryan Shrout

Nothing has changed on the issues in question.

March 29, 2013 | 05:15 AM - Posted by technogiant (not verified)

Thanks for the great article and all the work you've done guys.

I run 2x gtx 460's is sli and while I dislike screen tearing I've noticed that options such as vsync, active vsyn and frame rate limiters actually make the experience less smooth as appears to have been highlighted in this article.

I've considered getting a 120Hz monitor just so I can run without any of those options at a decent frame rate but use sufficiently high settings so as not to go above 120Hz and so incur screen tearing.

Thinking further I'd like Nvidia to develop a variation of their gpu boost technology that would actually down clock the gpu to prevent frame rates from exceeding the monitors refresh rate.....think this would give the benefits of no screen tearing without the negatives of vsync and the like.

Thanks again for the article guys.

March 29, 2013 | 05:37 AM - Posted by technogiant (not verified)

Actually using gpu boost dynamically to both under and overclock the gpu to achieve a target frame rate could be a very nice way of producing a smoothed experience without any of the negatives of other methods as its occurring directly at the gpu instead of in the game engine to display time line.

March 29, 2013 | 08:01 AM - Posted by Pick23 (not verified)

So is this article saying that even with the new testing methodologies:
1.Single card 7970ghz is still slightly better than the 680
2.Crossfire absolutely sucks
?

March 29, 2013 | 08:18 AM - Posted by John Doe (not verified)

7970 Ghz is slightly better than a 680 ONLY at stock.

When you're comparing 7970 Ghz to 680, things ENTIRELY depend on clock speeds since the 7970 Ghz is nothing more than a pre-OC'ed 7970.

But yes, CF does indeed sorta suck. Still.

March 29, 2013 | 07:26 PM - Posted by Anonymous (not verified)

Sweet 7970 still the best card under.. well under $1000 lol

March 30, 2013 | 09:21 PM - Posted by steen (not verified)

What's stock for a 680? ;) 7970 GE is slightly slower than Titan...

CF sucks just like SLI. What's your poison, input lag or frame metering? Do poeple understand what "runts" are? CF is actually rendering the frames, you just don't benefit as they're too close together. One frame renders the top 1/4 of the screen when the next frame starts. Your top ~200 lines are the fastest on your screen. ;)

(Sorry for the previous multi-posts. Don't know what happened there.)

April 7, 2013 | 01:15 PM - Posted by John Doe (not verified)

I have ran far more CF and SLi setups than you did FOR YEARS and understand far more abouts these things than you and your little silly mind does.

March 29, 2013 | 11:39 AM - Posted by fausto412 (not verified)

interesting piece, good job pcper.com

now I wonder if when AMD does a global fix my 6990 performance will be dramatically improved on bf3?

and what is the effect of correcting this to latency and actual framerate? will we see FPS go down at the expense of frametimes?

It is Obvious Nvidia was on top of this for some time...I just don't see a proper fix in 120 days.

March 29, 2013 | 12:24 PM - Posted by Chad Wilson (not verified)

Just out of scientific curiosity, did you do a run without the splitter in the mix to confirm that the splitter is not adding any latency to your tests?

March 29, 2013 | 12:33 PM - Posted by Anonymous (not verified)

Do people actually use vsync without some form of triple buffering?

I don't see how. Jumping between 30 and 60fps or whatever is not an enjoyable, nor smooth experience.

So, if you can enable vsync AND allow the game to sweep through a normal range of available framerates, does this negate the increased frame times of constantly switching back and forth between high fps and low fps?

March 30, 2013 | 12:56 AM - Posted by bystander (not verified)

V-sync, even with triple buffering, still jumps back and forth between 16ms and 33ms, but it does it between frames. A 120hz monitor helps here, as you can have 25ms frames too, so it is less of a variance.

March 29, 2013 | 12:36 PM - Posted by Anonymous (not verified)

Furthermore, is playing a game without vsync enabled REALLY an option?

Are you sure gamers all over the world disable it to be rid of the latency issues? I'm not so sure.

I'll happily take a little latency in a heated round of counter-strike than end up dead, or missing my shot because 50% of the screen shifted 8 feet to the right. (screen tearing).

Pretty much all games are unplayable without the use of vsync and I'm not convinced it's a personal preference, either, if you enjoy your experience while you're tearing frames - I'd just call you a mean name that insinuates you're not telling the truth.

March 29, 2013 | 02:00 PM - Posted by Marty (not verified)

If you are a competitive player, VSync is not an option, you are lagging an extra frame behind.

March 29, 2013 | 12:45 PM - Posted by rezes

Where is the new tests? and when?

March 29, 2013 | 02:20 PM - Posted by Anonymous (not verified)

So how much did nVidia pay you?

While I can see the potential in this kind of testing, and some of the issues you have mentioned are valid, you have drawn quite a bold and one sided conclusion using the competitor's software. I'll save my judgements for when this becomes open source.

March 29, 2013 | 08:12 PM - Posted by Fergdog (not verified)

It's not purely Nvidia made software, if you read the article or paid attention to this site you'd know Ryan co-developed this benchmark with Nvidia and he's been working on it for a long time.

April 2, 2013 | 11:10 PM - Posted by Anonymous (not verified)

nVidia has to do almost everything, the amd fans need to get used to it.

AMD's years long broken bottom line and years of massive layoffs and closings mean they claim they "weren't even aware of this issue !? !! "

- like every other total screw up AMD gets caught on with their dragon drawers on the floor next to their spider platform, buck naked in epic fail and presumably clueless...

Maybe we need some depositions and subpoenas of internal emails to see just how much they covered up their epic fail here.

March 29, 2013 | 08:00 PM - Posted by Fergdog (not verified)

Quick question, for adaptive vsync, you put it on half refresh rate didnt you?

March 29, 2013 | 08:02 PM - Posted by Fergdog (not verified)

Half refresh adaptive only really makes sense on 120hz monitors, not sure why you used that setting on a 60hz monitor for benchmarking.

March 29, 2013 | 11:06 PM - Posted by Anonymous (not verified)

Hoping you post the titan and and info today as promised!!!!!!!!!

March 29, 2013 | 11:07 PM - Posted by Anonymous (not verified)

Titan and amd

March 30, 2013 | 12:56 AM - Posted by MaxBV (not verified)

Waiting on that GTX 690 and Titan article still, hope you guys haven't forgotten.

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