3DMark adds Tier-2 variable rate shading test for Turing cards

The 3DMark benchmark suite was recently updated with support for Tier-2 variable rate shading (VRS). This test is currently exclusive to Nvidia Turing cards. According to patch notes for 3DMark 2.11.6846, the test "adds a new way to compare variable-rate shading performance and image quality." 

VRS is a feature that currently only works on Nvidia Turing and Intel Gen11 GPUs. It depends on the fact that not all parts of an onscreen image have the same apparent quality. For instance, objects in the background or objects subject to motion blur render with less fidelity than a player view model. VRS lets developers selectively reduce the pixel shading rate in specific parts of the image. This leads to performance gains with almost no loss to image quality. 

3DMark has featured support for Tier-1 VRS since last August. Tier-1 support enables developers to specify shading rates per drawing call. Tier-2 VRS allows for greater performance gains by letting developers specify different shading rates within drawing calls. 

In a blog post on the 3DMark update, UL Benchmarks provided before and after images to assess the impact of variable rate shading on image quality. We looked at these images on a 55-in 4K display and were hard-pressed to spot the differences. Certain objects, such as the marble pillars in the background, were ever-so-slightly softer. But the difference would be almost impossible to discern during gameplay. 

As display resolutions increase. with 8K panels on the way, intelligent techniques like VRS may enable developers to prioritize image quality without sacrificing performance.