Absolutely reasonable if your windows box is used for mundane web browsing / programming and the occasional video, but that doesn't fly for a gaming machine; some games will exhibit bad performance or will plain crash with old drivers that don't incorporate the regular fixes/workarounds added by nvidia (and amd does it too).
There's a youtube video I fail to find where a nvidia driver engineer explains how many games are terribly broken, failing to respect OpenGL/DirectX basics. Drivers hand-patch that, just like Microsoft hand-patch Windows for specific games "because compatibility" [1].
[1] http://www.joelonsoftware.com/articles/APIWar.html