Hi, I use FSX-SE DX10, with Steve's fixer. I noticed that my framerate was getting hammered approaching cruise altitudes, and quickly realized that it was the contrails: as soon as I descend to a level where there are no contrails, the framerate shoots back up. While the custom volumetric contrail effects look great, they literally cut my framerate in half when they're active. Not talking about just a small hit here! This seems to be a DX10 thing--the same thing happens with the FSFX contrails,