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Frame Rating: GTX 660 vs HD 7870, plus HD 7790, HD 7850, GTX 650 Ti BOOST

Author: Ryan Shrout
Manufacturer: PC Perspective

Skyrim - GTX 660 vs HD 7870

The Elder Scrolls V: Skyrim (DirectX 9)


 

The Empire of Tamriel is on the edge. The High King of Skyrim has been murdered.

Alliances form as claims to the throne are made. In the midst of this conflict, a far more dangerous, ancient evil is awakened. Dragons, long lost to the passages of the Elder Scrolls, have returned to Tamriel.

The future of Skyrim, even the Empire itself, hangs in the balance as they wait for the prophesized Dragonborn to come; a hero born with the power of The Voice, and the only one who can stand amongst the dragons.

Our settings for Skyrim

Here is a video our testing run through, for your reference

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Unlike the first three games we looked at here, Skyrim at first blush appears to perform as you would expect: both SLI and CrossFire are scaling in our observed, Frame Rating based results. 

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The Skyrim engine definitely has more stutter and frame variance issues but nothing overly dramatic.  The green and black lines that represent the single cards are fairly thin and consistent but both CrossFire and SLI have more variance.  All four cards have some pretty bad spikes and "hitches" - as any Skyrim player will report is the case.

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Skyrim definitely has an interesting pattern to our FPS percentile graphs with much more gradual declining metrics.  Keep an eye on the CrossFire and SLI results and how they do come close to meeting the performance of the single cards towards the end; in fact CrossFire does drop below the HD 7870 single card around the 90th percentile.

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Despite those issues, none of the four tested combination really add a lot of variance or potential frame stutter.  Our scale on the left hand side doesn't breach the 5 ms mark.

 

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Welp, at 2560x1440, the HD 7870s in CrossFire start to see some issues where the FRAPS FPS and Observed FPS are not matching up!  The HD 7870 single card is faster than the GTX 660 but let's see what happened to CrossFire.

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There are some obvious issues where CrossFire again falls into the trap of the alternating high and low frame times that we saw in BF3, Crysis 3, etc.  This lends more credit to the idea that we theorized in the first article - the more GPU bottlenecked the game session is the more likely we are to see CrossFire problems exhibited. 

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Based on the minimum FPS data you can see that the HD 7870s in CrossFire quickly become only marginally faster than the single card while SLI stays above the single GTX 660 throughout. 

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Frame time variance of the CrossFire configuration looks bad once again with much higher variance than the other configurations, but even at the worst case we aren't going much above 10 ms.

 

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At 5760x1080, even without HD 7870 CrossFire results, we some interesting issues with SLI and scaling.  While the extra GTX 660 adds performance in some areas, the results are consistent.

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Interestingly, even though there are a lot of areas where performance looks to scale well and with tight frame times, there are a lot of spikes and hitches in the game that kind of make SLI a poorer solution that we would expect.  That being said, the CrossFire results dropped so many frames from our capture testing that we couldn't even get a result!

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The Radeon HD 7870 does perform better than the GTX 660 card from NVIDIA (41 FPS vs 33 FPS) but we do see solid scaling on the SLI configuration (53 FPS vs 33 FPS).  The hitching issues seen in the frame time plot show up here as the sudden drop in the minimum FPS right at the 95th percentile.

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You can see that not only does the GTX 660 SLI setup have the most frame time variance, it also goes up steeply after the 90th percentile and to some pretty high rates - reaching 40+ ms.

 

April 5, 2013 | 07:29 PM - Posted by Torrijos (not verified)

Great work! I guess you're as happy as your readers to get to the end of this generation cards.

It would be nice, in order to facilitate readers choice, to have a summary page with all cards presents (maybe with dynamic selection).

What I image would be best is the graphs, where the reader selects a Game, a Screen Resolution, and gets all the cards on the same graphs (with tick-boxes to removes the cards he isn't interested in).

Graph= ƒ(Game, Screen resolution, GPU selection)

That way a reader looking for the best performance for his screen and favourite game would have all the information needed on a single graph. (you could be motivated to create another graph à-la TechReport taking into account the price)

Anyway Thanks again for the good work!

April 6, 2013 | 02:09 AM - Posted by Luciano (not verified)

thumbs up for this suggestion!
thats what here in brazil they call "info-graphics" (redundant i know by you get the idea).

April 5, 2013 | 08:28 PM - Posted by Cerebralassassin

Great work Ryan!

April 5, 2013 | 08:34 PM - Posted by ThorAxe

Thanks for a another great article. As a few others have pointed out it would be great to see older cards tested such as the 8800GTX, HD 4870 and up. I realize that this would be a huge amount of work but not everyone is a graphics whore like me that upgrades almost every cycle.

April 5, 2013 | 11:21 PM - Posted by Tim Verry

Ah, the good ole' 8800GTX. My little brother is running one of those still and when I finally upgrade he'll get my psuedo-6970 (unlocked xfx 6950). Unfortunately he missed out on my 3850 upgrade when it died on me and would no longer output anything to the display. It plays Kerbal Space Program, Minecraft, and most other games (with lots of stuff turned out of course) so yup, I would like to see Frame Rating through the several generations of graphics cards--even if it's only one card from each NV and AMD's generation and not their whole lineups (heh, we'd never see or hear from Ryan or Ken for 6 months if they had to Frame Rate all those cards :P).

April 6, 2013 | 02:12 AM - Posted by ThorAxe

I still have a HD 3850, 2x 8800 GTX, HD 4870x2, 2x HD 6870s and 2x GTX 570s SLI in various PCs of my wife and kids . My current gaming PC is 2x GTX 680s SLI. I told you I have a sickness. :)

At one point I ran a 4870x2+4870 in Trifire and it didn't seem as bad as the 6870s in Crossfire if I remember correctly, so it would be interesting to see what impact Trifire has on Observed Frame Rates.

April 6, 2013 | 02:25 AM - Posted by Luciano (not verified)

Your sickness gives you the power of intuition:

http://www.tomshardware.com/reviews/radeon-geforce-stutter-crossfire,299...

AMD fans: "see? you just need to buy a third card! im sure is cheaper than 2 nvidias"

April 6, 2013 | 01:32 PM - Posted by bystander (not verified)

Unfortunately only 1 card was tested, so conclusions are hard to be definite. What might have fixed it may be what fixes 2-way Crossfire, a CPU bottleneck. When you add more cards, the GPU puts more stress on the CPU, and if it couldn't keep up, it will bottleneck, which also has shown to fix stuttering.

More testing is needed. Same with V-sync. Only 2 games were used on the v-sync test. It may be that v-sync only helps due to its FPS limiting component, though I have a feeling it would help anyways, but more testing is needed to be sure.

April 6, 2013 | 01:34 PM - Posted by bystander (not verified)

I meant that only 1 game was tested, not one card.

April 6, 2013 | 02:20 AM - Posted by Luciano (not verified)

Maybe its time for you elite of reviews (pcper, techreport, toms, anand) get together to work on the data generation in gpu reviews.
The value of each reviewer is what he points for us to see more closely and his conclusions.
Toms for instance is saying "just turn on vsync and everything would be ok".
PCPER refuted that.
Thats why god gave us multi-tab browsing.

April 6, 2013 | 11:19 AM - Posted by bystander (not verified)

Unfortunately different people have different preferences. You typically find competitive gamers refuse to use v-sync, because it induces latency and you lose the advantage of high FPS.

And curiously enough, v-sync doesn't work with Eyefinity.

April 5, 2013 | 10:32 PM - Posted by bystander (not verified)

@Ryan:
I'm having a hard time finding what you are defining a runt frame. THG has it set to under 21 rows, which they said was the default, are you using the same definition, or something else?

April 7, 2013 | 04:07 PM - Posted by Ryan Shrout

Our versions of the scripts define it based on percentages.  If the frame is 20% or less of the preceding 10 frames average, then we consider it a "runt".

April 7, 2013 | 05:11 PM - Posted by bystander (not verified)

Cool, that is actually a cool method. The higher the FPS, the smaller the frames will be shown, so having it scale based on the average is good.

April 11, 2013 | 04:06 PM - Posted by Anonymous (not verified)

With 1080 horizontal "scan lines" on the average screen, calling 21 scan lines a frame is a joke really.

25% of one full screen would be 270 scan lines. Calling a quarter of a screen a "frame" is stretching it quite a lot.

Maybe one fifth the screen is a reasonable cutoff point, or one fourth. Anything less is a joke really, as once 5 "frames" are "sharing" one screen, we see slivered runts in all the examples given.

So I expect some reason for the answer, but I suspect we'll get ridiculous things like 7 or 8 scan lines out of over 1,000 on the screen "counts" as "one frame" or some tiny portion of the whole screen, far less than 20%, less than 10%, less than 5%, as 7 or 8 scan lines is less than 1% !

I can do the math, and do the visuals. Good luck arguing me down to 10% of a 1920x1080, or "108 scan lines" counting as one FPS.

April 12, 2013 | 04:42 PM - Posted by bystander (not verified)

I can't tell if you are arguing or agreeing with my thought.

I will add that as your FPS go higher, the smaller the slice of a frame will be on average. At 300 FPS, the average frame size will be about 20% of the screen. This is why I like what they did, as it scales based on the average frame size.

April 6, 2013 | 12:13 AM - Posted by Shambles (not verified)

Amazing timing! Needed exactly this.

April 6, 2013 | 12:31 AM - Posted by lindethier

Good work!

April 6, 2013 | 01:23 AM - Posted by Number1 (not verified)

I might have felt this dragged on a bit too long but I was wrong. It was important to do the tests across the whole line up of current cards. I was mainly concerned that you would end the investigation here, after doing so much work on this, but now that you have stated it is on going I am very impressed. Anyway just thought I'd say good work. Really good work. Very glad to hear that you will be looking at user submitted solutions.

It will be interesting to see if peoples claims about radeonpro etc are true. I have seen people post pretty impressive results in terms of frame latency using these solutions. I have also been promoting this solution going off other peoples reports. Hopefully there aren't too many costs associated with using it (other than setting up individual game profiles, and making sure you do it right..)

I agree with other users in that it would also be great to check say 6950s or 6970s in crossfire. AMD has suggested things like the GCNs memory manager needs work. AMD haven't specifically suggested that this is where crossfire is falling down and I don't think it's related. However, that isn't stopping people around the internet claiming it is the cause though. So it would be interesting to have a single non-GCN card thrown in, even if its only tested in two or three games, just to confirm it is AMD's whole crossfire solution rather than their GCN products and its memory management.

Good work nVidia in the last couple of years for making an SLI solution that works out of the box so well.

Good work to AMD for producing cards that are performing so well in the single card tests. Feeling pretty happy about my 7870 tahiti LE purchase.

April 6, 2013 | 03:33 AM - Posted by alwayssts (not verified)

Believe me when I say I understand that asking for more after all this feels terrible, and am greatful for the work on these articles but I do wish Ryan would test Tahiti LE...as well as show some 'typical' overclocking now that stock comparisons have been made.

It's very simple to argue LE is one of the most relevant cards for the largest market because of it's price/performance and absolute (overclocked) performance at 1080p, even if it's 'limited edition'/highly salvaged (which are usually awkward niche parts) and certainly soon to be replaced by Hainan...which will undoubtedly have a slightly better stock placement relative to 660ti. This is similar to the way '7870' became 7950 in performance through Tahiti LE, 7950B became the old 7970, and 7970GHZ ED was to have a stock config to beat the nvidia competition which often equaled or beat those original configs). Am I the only one telegraphing that coming stock above 660ti (which will drop to 250) with partner overclocks (like 7790 has with 1075/6400mhz) very similar to a stock 670 (but probably priced cheaper? Think 250, 270, 300, 330 (or something like that).

I would say I hope we get a 670/Tahiti LE update article, but I feel 670 is best left for when Hainan launches...and wonder if that is Ryan's thinking as well considering the deliberate choice to leave it out. I do wish both would've been thrown in the 660ti/7950B article, but understand his reasoning. 670 is in it's own price niche, just like 7870XT. I know the later may be a 'tweener, but it really would be interesting to see the results as I think it will show a nice point of reference/cutoff where most people should be looking to get smooth 1080p HQ game-play.

April 6, 2013 | 01:34 PM - Posted by Number1 (not verified)

Personally I think there is enough data to extrapolate how the gtx670 and tahiti LE will perform.

April 6, 2013 | 10:56 AM - Posted by AlienAndy (not verified)

More epic data !

April 6, 2013 | 04:50 PM - Posted by Joshua B. (not verified)

I am interested to see how crossfire/sli are effected by slower processors. I know that there is no end to the types of configurations out there but I wonder if causing a bottleneck elsewhere in the system will cause either adverse or positive results.

I also know that originally the setup used was to show the performance of the cards unrestricted, to which I say is a good thing when it comes to comparison from card to card, but now I find that adding in the cpu (crossfire/sli) may generate different results, unless you feel that the cpu still doesn't cause any "real" problems as far as perceived framerate. ex. the bulldozer review.

April 7, 2013 | 02:48 AM - Posted by Howie Doohan (not verified)

Shocking results from AMD. These results almost completely invalidate any price savings that might be had by going crossfire (eg CF 7970's vs SLI 680's). I'm definitely going green for my next multi card rig and won't be giving AMD a look until they pull their thumb out and fix crossfire.

April 7, 2013 | 09:03 AM - Posted by Humanitarian

Very comprehensive look at frame rating, excellent write up.

Really interested to see what some of software solutions previously suggested about will effect this problem.

April 7, 2013 | 11:34 AM - Posted by keromyaou (not verified)

A great work!!
I would like you to test older hardware (such as HD5870) to see when this crossfire problem occurred.
I found one link which might be interesting for you (http://www.tomshardware.com/reviews/radeon-geforce-stutter-crossfire,299...). Although the test in this link is not sufficient for withdrawing the final conclusions, it suggested that microstuttering was more in HD6870 crossfire than in GTX560 SLI setup and also that triple crossfire setup with HD6870 alleviated microstuttering greatly. Since their methods were not as finesse as yours, they probably were not able to detect some issues (like runts) like you were. But still their data is worth noting, I guess. I think that their data hinted that:

(1) Crossfire issues might be older than HD7000 series.
(2) Triple crossfire setup might be able to alleviate the problem which occurs with dual crossfire setup.

I hope that you have a chance to test triple crossfire setup with your apparatus as well as older gpu cards.

Thank you for your interesting data.

April 7, 2013 | 04:09 PM - Posted by Ryan Shrout

I think we are going to test one or two of the previous generations of cards to see how things scaled throughout.  Right now I am considering the HD 5870 and the GTX 480.

April 7, 2013 | 02:27 PM - Posted by Trey Long (not verified)

Great work. This is exactly the type of investigation that will make ALL companies better and go to a higher level.

April 7, 2013 | 06:27 PM - Posted by Anonymous (not verified)

Great test as always, but I think you should test GTX 580 SLI vs 660 SLI ASAP!
both have around the same performance, but Kepler supposedly deals with frame rate metering with dedicated hardware for that, and the 580 doesn't, both will use the same driver, from the same vendor, so it would be a great test and maybe help to understand how close AMD could get just with software tweaks!?

April 7, 2013 | 10:40 PM - Posted by I don't have a name. (not verified)

That is a huge amount of data presented Ryan. On the whole a killer article, one of the best I've ever read. The idea of testing the older 480 and 5870 should prove very interesting.

Thank you for such an informative, cohesive and thorough and downright geeky article. I loved reading through it. I think I went through the first article about five times just to ensure I had all the concepts fully understood. Awesome. :)

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