Disclaimer: Lotus Notes 8.5.2 is in beta and there are no guarantees that the features described here will be in the final product that IBM ships.
Being part of the design partner program for Lotus Notes 8.5.2 I just received code drop 5 i.e. the latest beta of Lotus Notes 8.5.2. Part of this release you are asked a new question while installing which is whether you want to enable preloading Lotus Notes when starting Windows (don't know if this goes for other platforms).
Now I'm on a SSD drive so my experience may be different from others on a "normal" spinning drive but it will be interesting to see how it performs and if it makes a noticeable difference.