Inkscape 0.48 now has a preference that allows users to take advantage of multi-threading for the Gaussian Blur filter. This filter makes one of the biggest impacts on Inkscape's performance when in use.
Mariana Sing uses blur throughout this image for subtle details, smooth color transitions, and numerous effects. Thankfully the blur operation is now faster than before when using a multi-core or multi-processor computer.
this one is amazing