Eximo :
Not sure where this 30-40% bottleneck is coming from either.
If you grabbed even a flagship GPU you wouldn't see too much trouble with the i3. You might have 10-15 FPS less than someone running an i7, but it won't be quite as dramatic as only running 30-40% as fast.
The GPU will do its thing most of the time. Just needs the CPU to feed it a little data. The CPU becomes a limiting factor when you run a game that requires more CPU horsepower. On high end recently released games you probably will perform less than others with faster processors, but you will still have that GPU available for less CPU demanding games.
Bottlenecks really only apply at the top end when you are trying to get the most performance out of a system. When you are mixing new/old parts you get what you get. You should spend the most amount of money you are willing on whatever computer component you are buying to maximize potential performance.
actually cpu matters a lot in BOTH the high end scenarios
AND the low end, with low resolutions where the cpu is the main fps determinator
also most new games are unoptimized poorly coded cpu hogs
well coded multi core games are the exception to the rule