To cure stutters on my own i7 system I set a BufferPool value of 300MB, which allows me to run extremely dense autogen stutter free. All that is required is lots of video memory. Those with a 1GB video card can often run 400MB buffepool, however high texture memory users like 4096 aircraft or cloud textures may require the bufferpool to be adjusted to a lower value. I run 2048 max and have no problems with a 300MB bufferpool on my 900MB card. If you search the forum here for "Miracle Tweak" you can read all about it. Otherwise here's my tweaking thread at Orbx. I suggest reading through the whole thing becuase my tweaks evolved during the thread as I completed more testing and fine tuned things.
http://orbxsystems.com/forums/index.php?topic=9908.0
BTW, regarding RAM usage a noted above, I was just doing some screenshot comparisons, and with LOD at 12 I was using a full 5GB of RAM.