You could use a lower cache size in MixEmergency, but this depends on a few factors, such as the dimensions of your videos (e.g. you can fit 4 times as many 320x240 frames into the buffer than if your videos are 640x480), and whether you have encoded them with fairly close keyframes (i.e. 25-40). I personally run MixEmergency with the cache size at around 300-400 MB, but I have all my videos at around 640x480 encoded to have keyframe distances of 25.
