Optimization gurus - please help!

Any performance or optimization gurus here?
Trying to determine what is costing me performance when I enter PIE mode. I go from 60fps to about 40fps.

Attaching the results of a stat RHI for both standalone and PIE modes. PIE mode is the bottom with the higher draw calls.

When you experience a 20% or more performance hit in PIE mode, what are typically the culprints?

I have Raytracing turned off and have only 2 dynamic lights casting shadows, everything else is baked.

if you are in 4.26 or 4.27 there seems to be a bug where ‘continuous’ updates to your RVT will cause your polycount to spike.

Using a virtualheightmesh, it’s a steady ~145k tris, but as soon as I check that box on the RVT it shoots up to the several millions.

Seems to be fixed in UE5EA2.

Thanks. I have VT enabled but not using RVT!

My draw calls seem to more than double when entering PIE.

Pretty sure this is where I am losing performance.

But what causes draw calls to increase if your scene isn’t changing?