As with all new releases, R45 brings performance improvements to wysiwyg.
The most noteworthy are the overall improvements to the speed of the application itself, i.e. “the UI”—user interface, which are noticeable when switching between Layout Tabs and between Modes. This is also used when performing Layer operations such as making them visible or invisible.
In addition, the Shaded View is now using a new texture compression algorithm which virtually eliminates delays in switching to a Shaded View, so delays that were once caused by imported high resolution textures are now gone. Such delays were noticeable while working in Shaded View, when Layers which contained objects using these textures were made visible.
Finally, a new option enables you to manually adjust (lower) the quality of the Shaded View beyond what the High/Medium/Low Quality setting allows, in order to increase performance; different files will require a different settings, but the performance increases can be significant.