From 60Hz to 30Hz: the pros and cons
To make up the shortfall somewhat, Playground implements its own form of motion blur in order to reduce the judder imposed by halving the amount of discrete frames that end up on your HDTV. While it can't hope to match the "full-fat" 60Hz experience, it's actually a really impressive piece of tech, seemingly more than just the simple camera blur you may expect. Looking at game captures frame-by-frame, the tech appears capable of picking out specific objects and blurring them individually according to distance from the camera and velocity - an object-based implementation in other words. Combined with the consistent frame-rate it works especially well in chase-cam mode where the camera is drawn back from the action, but its effects in mitigating judder aren't quite as pronounced in first person views where the difference between one frame and the next is that much more pronounced.
Over and above the fluidity of the screen update, the biggest challenge facing Playground in making Horizon feel like a Forza game was in retaining the signature physics and precision response. Forza Motorsport, famously, operates a 360 update per second system to ensure the authenticity of its physics, which ties in directly with the fast response from the 60Hz screen update. You can feel those calculations through the pad: input lag is very low indeed at 66ms - up to twice as responsive as many other racers we've played. Dropping down to 30Hz can have a fundamental impact on that low latency response. Up until now, only Criterion has managed to get close to giving that precision feel in a 30Hz title - famously, Need for Speed: Hot Pursuit cuts frame-rate in half compared to Burnout Paradise (and indeed, Forza Motorsport) but only adds 16.67ms - or one single frame - of additional latency.
Our input lag tests - measured with a combination of a Ben Heck latency controller monitor board and a high speed camera - suggests that Horizon adds two additional frames of latency to that found in Forza Motorsport 4, giving a total of 100ms. This isn't quite the same level of achievement as Need for Speed: Hot Pursuit (which based on the games we've measured is the most responsive 30Hz game ever made) but it's damn close. Indeed, prior to the release of NFS, many believed that 100ms was the lowest input latency possible on a 30Hz current-gen title.