I was playing around with a tool called "Topcat", visualizing Einstein@Home result files (the stuff that gets sent back to the server from your PC).
The first picture shows a visualization of an actual S5R2 result file (h1_0281.20_S5R2__65_S5R2c_4_0 to be exact).
The meaning is the following:
The sphere you see is the starsphere as seen in the "Screensaver" view. Think of it as Space with Earth in the center.
Every point in the sphere is a measurement point for a candidate pulsar, there are 10000 in each result (the 10000 most interesting ones), where the color of the dot also shows how interesting the candidate is: red are the most interesting, violet the least interesting). Because there can be multiple candidates at the same sky coordinate (for slighly different frequency and other search parameter), the Z-axis is also used to move the more interesting candidates to the outside of the sphere and the least interesting ones to the inside. So the few red dots that are close to the sphere's surface are the most interesting.
The following image is the same diagram for an actual S5R3 result (h1_0372.90_S5R2__83_S5R3a_1_0).
As you can see, only a segment of the sky is searched in this workunit, but in greater detail (the file still contains 10000 candidates = dots). Other workunits from this frequency series will cover the rest of the sky.
This might help to demonstrate why we see more variation in runtime in S5R3. The algorithm seems to choose certain parameters that are important for performance differently in different regions of the sky, which didn't matter in S5R2 as this averaged out over the complete sky. In S5R3, however, some WU are now "faster" than others.
The "Topcat" software is free, if anybody is interested I can post a How-To later how to visualize your own results (not that it makes sense, but just for fun).
I think this might be a cool addition to the current screensaver, if it's not too much of a memory and performance killer.