This implies to me that you have a dispersion problem. It is concievable that your 3i and driver have the same probable dispersion, since the driver goes further it gets you into more trouble.

Food for thought:
Do a "thumbs up" with your arm fully extended infront of you. When you look at your thumb it is covering about 2° of your field of vision. I know "so what". Now think of how many thumbs side by side it would take to cover your normal dispersion of your 3i - both sides of your target.

Here is the fun part (well I find it fun anyway).
Now multiply the number of thumbs by:
2 for 50yds out,
4 for 100yds out,
6 for 150yds out,
8 for 200yds out,
10 for 250yds out,
12 for 300yds out,
To give you an estimate of the width of your landing area.

For example, 200yd 3i with a 6 thumb dispersion (3 on each side of target) results in a landing area that is 48yds wide - ok for most open fairways but problem for tight 30yd wide holes. Driver of 250yds you are looking at a landing area that is 60yds wide.

Charles