leave (something) on the table
v. phr.β Β«Even a car straight from the factory will run differently with computer tuningβespecially if it is a performance-oriented model like the Mitsubishi Lancer Evolution or the Subaru Impreza WRX STi, equipped with beefy hardware like a turbocharger. βTheyβre so aggressively prepared from the factory,β said David Vespremi, who wrote βCar Hacks & Mods for Dummies.β βAnd yes, they left a little bit on the table. And that little bit is often what you get from tuning.βΒ» ββNeed a Tuneup? Become a Hacker” by SeΓ‘n Captain New York Times Oct. 25, 2006. (source: Double-Tongued Dictionary)