When it comes to performance, Nintendo has always aimed to deliver a rock-solid 60 frames per second with each home console Mario Kart and, aside from Mario Kart 64, it has always managed to achieve just that. There was never any doubt that Mario Kart 8 would fall right in line with the rest of the series but upon seeing it for ourselves we immediately noticed that something was amiss. During gameplay we experienced the regular appearance of duplicate frames manifesting as a constant but subtle stuttering effect. Upon analysis we determined that the game suffers from extended clusters in which a duplicate frame is displayed every 64 frames. What this ultimately means is that, during normal gameplay, Mario Kart 8 continually drops down to 59fps. This may not seem like a big deal - most will probably not notice it at all, and it has zero affect on playability - but it has a noticeable impact on image fluidity that mars what would otherwise be a perfectly consistent frame-rate. And for us at least, once it is seen, it can't really be unseen.
What makes this situation all the more strange is the fact that this problem only appears when CPU opponents are active. In time trials or split-screen matches, with AI-controlled drivers disabled, the frame-rate updates flawlessly while race introductions and victory animations all display correctly as well. The frequency and pattern of this problem suggests an internal timing issue, potentially related to Mario Kart TV, rather than one of performance. We can't be certain where the root cause lies but we certainly do hope Nintendo will take time to correct this problem in a patch.
Unfortunately, two-player split-screen operates in much the same way, suffering from the same frame-rate disturbances of as single-player, provided CPU racers are enabled of course.
