DX12: FCAT Frame Experience Analysis Rise Of The Tomb Raider
With FCAT on the following few pages, we will look into Frame Experience Analysis. With the charts shown we are trying to show you graphics anomalies like stutters and glitches in a plotted chart. Lately there has been a new measurement introduced, latency measurement. Basically it is the opposite of FPS.
- FPS mostly measures performance, the number of frames rendered per passing second.
- Frametime AKA Frame Experience recordings mostly measures and exposes anomalies - here we look at how long it takes to render one frame. Measure that chronologically and you can see anomalies like peaks and dips in a plotted chart, indicating something could be off.
Frame time in milliseconds |
FPS |
8.3 | 120 |
15 | 66 |
20 | 50 |
25 | 40 |
30 | 33 |
50 | 20 |
70 | 14 |
We have a detailed article (read here) on the new FCAT methodology used, and it also explains why we do not use FRAPS anymore.
Frametime - Basically the time it takes to render one frame can be monitored and tagged with a number, this is latency. One frame can take, say, 17 ms. Higher latency can indicate a slow frame-rate, and weird latency spikes indicate a stutter, jitter, twitches; basically anomalies that are visible on your monitor.
What Do These Measurements Show?
Basically, what these measurements show are anomalies like small glitches and stutters that you can sometimes (and please do read that well, sometimes) see on-screen. Below, I'd like to run through a couple of titles with you. Keep in mind that average FPS matters more than frametime measurements.
Rise Of The Tomb Raider Frame Experience Analysis
Above, a percentile chart of the first 31 seconds @ 2560x1440 of the benchmark recorded. In this particular chart we plot FPS and place it in relation to percentiles.
- If you look at the X axis at 50%, that is 50% of the time measured frames, while not 100% accurate as thesis, you can consider this to be the average frame-rate (this is the intro scene where Lara walks over the snowy mountain). Here a higher line = better
Now we move to latency measurements (frame-times / lower line is better). Above, the GeForce 1080 rendering Rise of the Tomb Raider at 2560x1440.
Above the Radeon RX Vega 64. On this 31 second run the graphics card manages extremely well; as you can see, there are no weird stutters recorded. At the end what you see is the benchmark scene change towards scene #2, so that is not an anomaly, however the FPS stops for a second during that scene change, and sure that is something visible.
So on each benchmark page I will add one extra FCAT result, in here you can see the two cards in an overlay for comparison's sake. This really is as perfect as can be.