Major performance drop with instanced meshes since PhysX 3.4 upgrade

Major performance drop with instanced meshes since PhysX 3.4 upgrade

Regression: YES
Worked: 3172292 (4.13.2)
Broken: 3249277 (4.14.3)

For me, my results were:

4.8 through 4.13
No Collision - 340 fps
Collision Only - 260 fps
Physics+Collision - 80 fps

4.14 and 4.15
No Collision - 280 fps
Collision Only - 100 fps
Physics+Collision - 32 fps

1. Open attached project in 4.13 and enable "Show Frame Rate and Memory" in Editor Preferences>General>Misc
2. Bring up the console and enter "t.maxfps 500"
3. Open the map from the content browser
4. Select the only blueprint in the level
5. Set Mode to 0 (No Collision)
6. PIE and note Frame Rate
7. Repeat with Mode 1 (Collision Only) and 2 (Physics+Collision)
8. Upgrade project to 4.14 or 4.15 and repeat

Result: Severe drops in performance from 4.13 to 4.14
Expected: Maybe some performance difference because of PhysX 3.4, but nothing this significant (see description)