AMD Catalyst 13.8 Beta Frame Pacing CrossFire Driver

Has stuttering with CrossFire been getting you down? Today may make many AMD CrossFire owners happy. Catalyst 13.8 Beta includes Frame Pacing technology to create a more fluid CrossFire experience. At least up to 2560x1600 resolution, for now. Does it really do the job? We investigate this and tell you what the gameplay experience is like.

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Frame Pacing Frame Time Constancy

On this page we are going to look strictly at frame time. That is the frame time as reported by FRAPS. FRAPS will output each frame into a .CSV file, with the frame time associated with each frame. We are using a 3rd party utility called FRAFS Bench View strictly to parse out the frame time CSV file into a meaningful graph format. You input the CSV file, and it outputs a graphed out form of the data.

On the graph you will find the time in milliseconds each frame took to render, the time in milliseconds is on the Y axis. On the X axis you will find each frame, as in real-time. We utilized the entire run-through of data to plot out our graphs. Therefore, the X axis shows you the length of the run-through, representing each frame as time progresses, and the bars move up and down depending on the time in milliseconds.

Here is the important part, what you want to look for is the Average Frame Time. Ultimately you want your frame times to all be consistent and closer to the average, rather than peaking or dropping well below the average. This shows consistency, if the bars are closer to the average and do not deviate as much.

What will be interesting is to see how this reacts with Frame Pacing, since Frame Pacing can delay frame times in order to smooth out consistency. That means we may see some high peaks, or drops, but the subsequent frames should not be so abruptly different. We will see how this works out, frame time is something that takes a bit of understanding.

In each set below, the first graph represents Frame Pacing OFF and the second graph below it represents Frame Pacing ON. All in-game settings are exactly the same as the previous page. You can click each graph to make it bigger.


Crysis 3

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Here is what to notice, if you look between the top graph and the bottom graph, comparing these as a whole, you will find the top graph with Frame Pacing Off is as a whole fatter and wider vertically. The bottom graph with Frame Pacing On is more narrow, vertically, meaning it is keeping closer to the average, while the top graph has more peaks and valleys making it farther apart from the average.

This shows that turning on Frame Pacing is making the frame time more consistent and closer to the average, rather than having an overall more distance of frame time from the average. Basically, there are a lot more bars over 33.3ms with Frame Pacing Off, compared to Frame Pacing On. Still, it is not perferct. We have some frames taking upwards of 80ms, and one jumped up to 140ms. Overall, it is an improvement that translates to feeling the difference as you play the game.

Far Cry 3

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Out of all the games we played on the Radeon HD 7990, Far Cry 3 was the most inconsistent and choppy. Even with Frame Pacing turned on, it was stuttery feeling, but this lagginess was reduced slightly with Frame Pacing.

You can tell in the frame time graph above with Frame Pacing Off how erratic the game is. There are loads of frames that shoot past 60ms, and a lot between the average and 33.3ms. The average overall is lower in this game because it is so erratic. This graph is a good representation of a game that has very bad consistency and fluidity.

Now look at the graph on the bottom with Frame Pacing turned On. There is vast improvement in the average to 33.3ms range. The frames are much closer to the average. However, there is still a ton of frames past 40ms that cause the game to stutter and feel choppy as we played the game. It was not a good experience, but it was slightly better with Frame Pacing enabled.

Hitman: Absolution

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Hitman is very interesting, there is little change in the frame time consistency as far as this graph goes. The most change is during the beginning of the run-through, there are some consistency improvements with Frame Pacing. What we really find odd, and hard to understand, why are some frames going up to as long as 820ms! Maybe a bug here, maybe not.

Metro: Last Light

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Metro: Last Light also shows consistency improvements with Frame Pacing turned On. In the top graph some frames reach as high as 50ms, but in the bottom graph they mostly stay below 40ms. The entire plot area is narrower and closer to the average with Frame Pacing turned On. The top graph has more peaks and valleys. The average is moved to a lower ms range, which is what we want.

Tomb Raider

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You can drastically see an improvement in Tomb Raider. This game shows you what good Frame Pacing looks like in a very visual way. The frame times are being pulled in much closer to the average, with a narrower amount of erratic frame times, with Frame Pacing turned On. The ultimate in consistency would be a solid line, without much deviation. You can see with Frame Pacing turned On in this game we are closer to that reality.

Summary

Frame Pacing works. Ultimately you want a smooth line of frame time, without much deviation, and you want low frame times. You also want the frame time to stabilize around an average, without many peaks or valleys. Consistently with Frame Pacing Off frame times are wild and erratic. Frame Pacing is pulling the frame time in and making it more consistent in every game. However, it still is not perfect, there are still some wild frame times that we don't quite understand why. This is definitely a foot forward in the right direction from AMD though, but work still needs to be done.