Yeah, it's called cache. If you are experiencing lag when FFWDing and find that all your movies take 5-6 seconds to start - then I think it's time to lower the cache size. Either do this by dropping the number in the 'precache before starting playback' to either 1 or 0. It takes 2-3 seconds, but then you should get better results during FFWD/REW. And if you have set a specific <cachesize> tag with each share then it might be good to lower it. I set the default cache size for each of my video shared folders to 8192 K first - then dropped it to 4096 K after experiencing heavy lag.