I wondered whether it was due to a character I was using or the dress or something else so I tried it with a basic G3F, no morphs, standard skin, base resolution and no subD.

But no, I still get the same. I have a brand new NVidia 1070 GPU (whereas when I was testing last year I was using a NVidia 970). I use an Intel Skylake processor with 32GB RAM - here are the specs.

Intel Core i7 6700 Cores 4 Threads 8 Name Intel Core i7 6700 Code Name Skylake Package Socket 1151 LGA Technology 14nm Specification Intel Core i7-6700 CPU @ 3.40GHz

NVIDIA GeForce GTX 1070 Manufacturer NVIDIA Model GeForce GTX 1070 Device ID 10DE-1B81 Revision A2 Subvendor ASUStek Computer Inc (1043) Current Performance Level Level 0 Current GPU Clock 139 MHz Current Memory Clock 405 MHz Current Shader Clock 405 MHz Technology 16 nm Bus Interface PCI Express x16 Temperature 35 °C Driver version 21.21.13.7633 BIOS Version 86.04.26.00.83