1.) In general, the VRAM usage for textures is still way too high compared to Pre-PBR (V6) viewers. For example a simple scene with 3 avatars visible, a few palm trees and void water in the background, almost 3GB of VRAM was used for textures!

2.) Texture bias calculation is bugged and can lead to constant up- and downscaling of textures: If an over-budget of VRAM is detected, the discard level is increased. When memory is available again, the viewer slowly reduces discard level until an over-budget is detected. Then the cycle starts again and the viewer will never stop and reach a stable state. This is accompanied by the CPU constantly ramping up and spikes in frame times every 4-5 seconds, making it an awful and unpleasant experience. Here is a video of the problem when observing the texture console: https://gyazo.com/57cb4d19a9cd24eea22a4a8f0e52fcd2

3.) Bug #2 in texture bias calculation (in LLViewerTexture::updateClass()): While downscaling textures by increasing the discard bias, the viewer waits 1 second after a downscaling before another possible downscaling happens. However, if memory isn't low anymore, the decrement of discard bias and upscaling of textures happens every frame.