How We Tested The OSVR HDK 1.4
Typically we test with an X99-based system with an Intel Core i7-5960K. But for this story, we went with an older build since our reference machine is configured for use with the Rift and Vive. It's based on an Intel Core i7-2600K, 16GB of Corsair Vengeance DDR3-1600, a 250GB Samsung 850 EVO SSD and a 2TB Seagate Barracuda plugged into an Asus Maximus IV Gene-Z mATX board.
We didn't bother benchmarking a lot of graphics cards. We're still working on a methodology for measuring performance in VR, after all. Instead, we used a Gigabyte GeForce GTX 980 Ti Xtreme Gaming to minimize graphics bottlenecks as we evaluated the OSVR hardware. And to test whether a GeForce GTX 660 could really drive this platform competently, we dusted off an old reference card to validate those claims.
|Products||Gigabyte GeForce GTX 980 Ti Xtreme Gaming||Nvidia GeForce GTX 660|
|Max Core Clock||1216 MHz||980 MHz|
|Max GDDR5 Transfer||7.2 GT/s||6.0 GT/s|
The VRMark latency test measures the time it takes between a draw call and an image to display inside the HMD, evaluated via external sensor. Software is then able to determine draw latency, response time and frame persistence. If you want to learn more about how the test works, see our VRMark preview.
The sensor that we use in conjunction with VRMark to perform the latency test can only measure one lens at a time, so each eye must be evaluated separately. When we tested the Vive in early May, we found that each screen achieved similar latency scores. In the Vive (and Rift), each eye gets its own panel. This allows both to initiate at the same time. The OSVR HMD has a single 16:9 display, so one eye will always draw slightly later.
In our case, the right eye turned out to be faster. We recorded 102ms of total draw latency, response time was 28ms, and frame persistence was 30ms. The fall time for the right eye was 11.22ms, which is roughly 4ms longer than the Vive.
The left eye was somewhat slower to react with a total draw latency of 111ms. The response time of the left eye was the same as the right at 28ms, and the frame persistence was slightly lower at 28ms. The fall time for the left eye was 2ms higher than the right, at 13.35ms.