A person who thinks they are good at optimizing their electronics, computers and other equipment, but suffer severely from confirmation bias. Bientists "buy into" ridiculous, half-baked and often overkill solutions usually out of a combination of impatience and arrogance. Rather than doing any verifiable research or empirical experimentation, they base their techniques on correlations, isolated incidents and things they read once on a forum, usually posted by other bientists. If a confirmation bientists finds another confirmation bientist with the same ideas, their ignorance is locked in for life. See also: bientist.
Any confirmation bientist will tell you that disabling all the services in Microsoft Windows and turning off automatic updates will make everything run better and faster with minimal internet lag.