I don't know what resources are mentioned too, but 8X works for me most of the time ("most" means about 2/3
) . An exception is when the system is overcrowded or battles are going on. Generally, if to many ships get into scanner range speed drops to 4X. My comp is about 2 years old so nothing special.
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A little hint that I've found in the russian 1.1 patch descrition. "Implemented the acceleration time of 8. With the lack of performance mode automatically turns off."
"performance mode" - probably that in windows settings. Maybe this will help you.