My game’s default settings are:
GI Bounces: 1
GI Samples: 6
GI Upsampling: 25%
I give the player controls to adjust those (I’m finding not every upsample resolution is relevant). 25, 50 and 100% seem to give clear results in both perf and quality. The lower upsample rate of 25% definitely reduces quality and makes the result muddier, but it makes GI performance tolerable. 2 Bounces look better for sure but it comes at a noticeable performance cost. 6 Samples seems to keep the GI noise to a minimum along with the 25% rate but doesn’t impact perf too much.
My scenes are all dynamically lit and Ray Traced. With GI off perf is around 90fps, with GI on (using the default settings) its more like 55-60. My hope is that GI will get better over time, maybe by the time UE reaches 4.24 they’ll have all the quality and perf issues sorted out.
GI rendering quality looks better in 4.23 but the denoiser dance is still present. The noise dance is a different result than 4.22, and it may be improved. Right now I can just tell that its a different but still noisy result.
But I have seen RT performance is absolutely better. I have some scenes where a reflected image can consume the screen, and in 4.22 this would cut the framerate in half. In 4.23 there’s no perf loss at all.