I was told that frame rates over what you can actually see tells you very little about the actual performance. So implementation A at 315 FPS being 10% faster than B might very well be 50 % slower than B at 60 FPS.
What is interesting is if the frame rate can keep a steady 30/60/120 FPS. Anything above that is just not indicative of actual performance.
Bare in mind that Valve is running this test on a much higher end PC than most consumers are likely to have. People will want to be able to run these games on their $500 laptops , so the difference between 270 and 315 FPS might translate into a difference between 50FPS and 60FPS which would be noticeable.
...or it might not. Which is the problem. You can't just interpolate like that.
Or can you? I have only heresay to go on.
That is a headroom of a factor of 5.25. If you use that headroom to implement better graphics, your performance characteristics will likely change completely.
That's the point. A thousand vs. a million FPS when you draw a single unshaded triangle doesn't necessarily interpolate to predict the performance in a real scenario.