Reduce the number of slices by 2x

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/Volumetrics/Resources/VolumetricLighting.compute

 #if (SHADEROPTIONS_VOLUMETRIC_LIGHTING_PRESET == 1)
     // E.g. for 1080p: (1920/8)x(1080/8)x(128) =  4,147,200 voxels
     #define VBUFFER_TILE_SIZE   8
-    #define VBUFFER_SLICE_COUNT 128
+    #define VBUFFER_SLICE_COUNT 64
-    #define VBUFFER_SLICE_COUNT 256
+    #define VBUFFER_SLICE_COUNT 128
 #endif
 
 #define SUPPORT_ASYMMETRY       1 // Support asymmetric phase functions

ScriptableRenderPipeline/HDRenderPipeline/HDRP/Lighting/Volumetrics/VolumetricLighting.cs

         switch (preset)
         {
             case VolumetricLightingPreset.Normal:
-                return 128;
+                return 64;
-                return 256;
+                return 128;
             case VolumetricLightingPreset.Off:
                 return 0;
             default: