Viewport framerate reduced by over 1/2 when IR is running on simple scenes

[danio1011]

Hi all,

I'm not sure if it's a windows update, a driver update, or the latest Corona but I've noticed a BIG drop in viewport performance when IR is running even on relatively simple scenes.  I don't recall this happening as much even just a month or so ago.  I just tested a couple scenes and am seeing drops from 30fps with IR not running to 10-13fps just with IR running.  Very chunky and slow interaction.  Not using forestpack or floor gen.

I've tried updating my nVidia drivers (latest studio...should I be using game ready?), tweaking # of threads used, disabling windows firewall, setting exceptions for real-time threat, turning off all exploit protection, etc.  I'm starting to wonder if this is QT related or else something to do with the latest Windows cumulative update (2004.)

System specs:
3990x (not OC'ed, ram tested with XMP on and off same results)
128gb ram
2080 Ti
Max 2020
Corona 6 stable
Logitech MX Master 2S wireless mouse
Wired keyboard

Thanks for any insights, my last resort will be to try an older or newer max version or an older Corona version....but none of those feels like a 'solution.'

Cheers,
Daniel

[danio1011]

Update:  I massively improved my UI lag by setting a QT variable for 'Angle.'  Perhaps this means I should try different nVidia drivers to see if they deal with OpenGL better since my understanding is this override makes QT use DirectX instead of OpenGL.  I went from clicking and having a 2-3 second lag before my selection would 'take' to getting instantaneous feedback now.  This behavior often happened with or without renderings going on.

Update 2:  The lag comes back later in the session, even with the QT variable set.  Starting to feel like it's definitely video card related.

Update 3:  Disabling SMT on my 3990 seems to reduce the framerate drop of IR by almost exactly 50%.  So instead of 20fps dropping to 10fps during IR, it drops to 15fps.  Weird. 

Viewport framerate still drops by 50% during IR, and UI lag comes back more or less.  The investigation continues...





QT info, I believe this shows up on the Corona helpdesk too: https://knowledge.autodesk.com/support/3ds-max/troubleshooting/caas/sfdcarticles/sfdcarticles/3ds-Max-UI-lags-or-seems-sluggish-even-on-very-fast-multi-core-CPUs.html