Hello Carnnage,
Did you ever find a fix for this? I am having the same issue and I am no where near disk usage limits, I have 2 evo ssds in striped raid. I have 2 x x5670 CPUs and 144gb of ram. I am only running a 3x3 grid and when redis saves my memory usage goes from about 32gb up to 60gb-70gb and I sometimes getting lag spikes over a minute. If shadow drive will help and anyone can guide me through doing it, please let me know. Im using windows 10 Pro.