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

Battlefield 3 (DirectX 11)

Battlefield 3™ leaps ahead of its time with the power of Frostbite 2, DICE's new cutting-edge game engine. This state-of-the-art technology is the foundation on which Battlefield 3 is built, delivering enhanced visual quality, a grand sense of scale, massive destruction, dynamic audio and character animation utilizing ANT technology as seen in the latest EA SPORTS™ games.

Frostbite 2 now enables deferred shading, dynamic global illumination and new streaming architecture. Sounds like tech talk? Play the game and experience the difference!

Our Settings for Battlefield 3

Here is our testing run through the game, for your reference.

Right away with the Radeon HD 7870 we see a difference between the FRAPS measured frame rates and the observed frame rates of our Frame Rating capture based analysis system.  In many areas we found the performance of the CrossFire configuration to be no faster than the single GPU, when we see large amount of alternating full frames and runt frames. 

Worth noting of course though is that the single GPU results are showing the HD 7870 as the superior card compared 1 on 1 with the GTX 660.

Our frame time diagram shows where those drops in observed frame rates happen and WHY we measure them that way.  The GeForce GTX 660s in SLI though result in a pretty steady frame time sequence with very little variance.

This graphs shows the percentile distribution of frame rates, effectively your minimum frame rate level at any given percentile.  You can see that the "average" frame rate of the SLI configuration jumps from 59 FPS to 110 FPS or so, while the CrossFire only increases from 61 FPS to 80 FPS. 

Our data shows a high level of frame variance on the CrossFire result as you would expect based on our frame time plot above. 

The same pattern is seen at 2560×1440 as we witnessed above at 1920×1080 – the CrossFire result sees significant runt frame counts and because of that the "observed" frame rate drops noticeably.  Also, the GTX 660 is running consistently slower than the HD 7870 in a single GPU scenario.

The frame time graph looks even worse at 25×14 than it did above with more frequent episodes of alternating runt and long frames displayed to the gamer.  The SLI results do show a bit more variance as well though nothing close the ballpark of the CrossFire numbers.

Comparing the orange (CF) an the black lines of the HD 7870 there is very little difference between the observed performance based on FPS percentile data.  In fact, towards the end we see the CrossFire results dropping under that of a single card.  The GTX 660s running in SLI though are much better with the average FPS scaling from 36 FPS to 68 FPS, an increase of 88%.

Clearly the frame time variance and potential stutter seen in the Radeon HD 7870s in CrossFire are a problem, shown here in another light.  The SLI configuration does see more variance than the single GPUs but it doesn't really get bad until we hit the 95th percentile.

At 5760×1080 running in either AMD Eyefinity or NVIDIA Surround, the HD 7870s in CrossFire exhibit more problems, this time in the form of dropped frames.  Once we take those out of the calculations we see performance at or below the results from the single HD 7870.  NVIDIA's GTX 660s in SLI though scale consistently as you would expect.

For single card results though, the GTX 660 is definitely falling behind the HD 7870.

That blob or red shows you the dropped frames that are missing from the colored overlay that we expected to see.  One of the Radeon HD 7870 GPUs is basically doing work that is never seen by the user…

The CrossFire results look really bad in our frame time plot but even the GTX 660s in SLI are showing some higher than expected frame time variance.  Compare that to the slower, yet more consistent frame times on the single HD 7870 and GTX 660 and you can see why multi-GPU simply produces more complicated issues for developers and GPU vendors. 

Our frame rate graph definitely indicates that SLI is scaling with an average frame rate that increases from 22 FPS to 37 FPS but that SLI does tail off at the end.  In the worst cases here (99th percentile) we only see scaling jump from 16 FPS to 20 FPS.  CrossFire never is able to separate from the single HD 7870 results.

Because we remove the dropped frames all together from the CrossFire data, it appears that the frame variance levels of CrossFire HD 7870s is LOWER than the GTX 660s in SLI – and that is true in the purest sense.  Frames that never show up on the screen can't "vary" from the running average of previous 20 frames!