A maximum-detail run through a Nürburgring replay in Project CARS yields a fairly consistent benchmark. This is perhaps the most demanding workload in our suite—even a GeForce GTX 1080 Ti is forced to its knees by extreme levels of anti-aliasing.
All five platforms are hammered by Project CARS’ top detail settings, imposing ASW across our 80-second test sequence.
As we’ve become accustomed to seeing, AMD’s FX-8350 incurs the highest frame times. Occasionally, this means ASW has to synthesize two frames for every real one. A series of spikes in the first quarter of our benchmark cause the same issue on Core i7-7700K.
Those anomalous spikes cause Core i7-7700K to trail Intel’s Core i9 in our average unconstrained frame rate graph. Of course, this came as a surprise to us, so we asked the Slightly Mad Studios team to weigh in on our findings.
From our discussion, it sounds like Project CARS doesn’t specify thread affinity on the PC, so all available threads are, in fact, utilized. However, the benefit of this depends on the granularity of tasks being scheduled and dependencies that might result in a stall. There is, then, a saturation point where the advantage of more cores bottoms out.
Cache utilization can become a factor as well. SMS CTO and technical director Ged Keaveney adds, “we are sensitive to [L2 cache usage] on some of our threads, and that can have a big impact depending on the thread topology the OS scheduler chooses. They tend to only care about available time slices and not cache usage, so patterns can occur where multiple cache-heavy threads can end up on the same cluster and the caches get hit harder.” Taking that information into account, in addition to the Core i7’s troubled first quarter, helps explain how Core i9 might establish its lead.
The jump between our 95th and 99th percentile frame times on Intel’s Core i7-7700K is wholly attributable to the benchmark's beginning sequence, culminating in a worst-case 43ms frame. Through most of the test, though, Core i7 is well-behaved.
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