Spring RTS Engine

No but it's like a car that goes 1 mph faster than another...

If we're talking about games that already get like 300 FPS maby. 60FPS vs 55FPS is a reasonable difference. 35FPS vs 30FPS is a huge difference.

I still wouldn't call it outperforming, most of the time it's a driver issue which gets fixed over time... usually.

Or a quirk of an individual engine which does not reflect on the "raw" performance of a given brand of video card. Plenty of video cards perform better in some situations and worse in others, compared to the other brand or even another model.