[Russell Sobie]

Probably the video ram, but might also be the OS. I've been on both a GeForce 970 4GB and a GeForce 1070Ti 8GB, on Windows 10 Home 64bit. That said, Mudbox will still crash if you look at it funny, even on my faster box. Save early and often once you do get a beefier system!

Here's the two sets of specs for both of my recent rigs:

I5-6600K @ 3.50Ghz
16GB RAM
Geforce 970 4GB
250GB SSD
Windows 10 Home 64bit

I5-9600K @ 3.70Ghz
16GB RAM
Geforce 1070Ti 8GB
500GB SSD
Windows 10 Home 64bit

The latter I built for ~1000 USD just before the holidays. Good luck!