They are generally not chips anymore. It is more likely to be a re-flash of your ECM. If you have a turbocharged vehicle, you can get some significant gains. If you have a normally aspirated vehicle, power gains are minimal; although you might gain some benefits in shifting etc.
Also, remember that your powertrain warranty is likely to be adversely affected. If you have a powertrain problem, you are likely to be on your own.
2012 F150 FX4 Ecoboost, 2016 Surveyor 274BHS
2003 Yamaha FJR1300, Demco Premiere Slider
1969 John Deere 1020, 1940 Ford 9N, 1948 Ford 8N
Jonsered 535, Can of WD-40, Duct Tape
Red Green coffee mugs