Welcome to Subsim (your better off here anyway
)
To answer you're question directly - I have never actually played the tutorials so I'm not too sure. However, one thing springs to mind, have you got AA + AF maxed out on you card?
Next, comes the big question. Are you playing Stock SH3? If so there have been significant improvements with this game.
Firstly, get yourself the offical Patch 1.4b.
Then have a look at the supermod options.
You currently have a choice from GWX, NYGM 2.3 & UBWAC.
Now, without covering really old news, the basics are that these three all offer improved realism (not too much but certainly more than the standard box version). Also, GWX & UBWAC offer improved graphics & sounds.
Being a GWX user (slightly biased :p) I would say that GWX offers the best allround package, you will surprised at the changes made.
The short of it is, you can find alot of info here and in the Mods section. Also, we will always help if we can.
Again, Welcome Aboard & Enjoy your Stay.
Edit - See the Newbie Links -
http://www.subsim.com/radioroom/showthread.php?t=96026 I'm not sure how upto date this is but it's a good start.