Just a little feedback for raytracing in 4.26 (I am using a copy of my project that was originally setup with 4.25):
The project (running on a 3080rtx) uses ratyraced: shadows, AO, reflections and GI (bruted forced with 2 bounces and 4 samples). All lighting is dynamic. To keep frame rate playable on an 3440x14440 screen r.ScreenPercentage is at 75 and r.Raytracing.GlobalIllumination.ScreenPercentage is at 30. Three different directional lights shine the scene, but almost no local lights. Geometry is very basic at the moment.
With 4.26 and no changes I am losing about 5% of fps (eg from 56fps to 53fps). What’s worse, the picture is very noisy suddenly (as if I would use less samples for GI). Many more graphical artifacts from the few local light sources. Brightness seems increased. On the other hand, the gI effect appears a bit more intense (color bleed). Finally, after a while I get flickering glitches which make a restart of the editor neccessary.
I hope this helps in developing the engine further and I also would appreciate any hints on how I could improve the experience (make it more like 4.25 was).