Drivers themselves are mostly tiny, generally 1MB or less.
There's a trend towards "Full Featured Packages" from driver manufacturers that deploy 17 different apps They Thought You Would Like To Have, such as their exclusive systray volume control knob, in case you were dissatisfied with the other one, plus that annoying popup splash at boot time, plus the random rundll32 errors which they didn't intend but they hope you're enjoying anyway... oh, and maybe the driver itself, as an afterthought.
Still, 3.46GB sounds huge, even by those standards. Are you sure it's not a folder that contains many different versions of their Full Feature package?