Hold on...if the numbers on the left are hours spent on the computer....how is it possible to have over 1000 hours in 6 days?
Three ways:
1) I have MORE THAN ONE COMPUTER running the software, and
2) Any ONE of those computers may have one OR MORE "cores" or "GPUs" (Graphics Processing Unit, in the graphics device) dedicated to run the program SIMULTANEOUSLY, and
3) Each of the above might be running at a rate that is faster/higher than "average required to do the task" which allows them to complete an estimated "one hours task" in just 30 clock-time minutes.
'Hope that answers your question!
P.S. I can have two of my Q6600's quad cores dedicated to run ALL THE TIME - even while playing Halo, being on vent, running Fraps (and recording my gameplay), running a system monitor, and listening to music with winamp. So basically two of my cores are ALWAYS running SETI@home. And when I'm not at my machine, it switches over to use the GPUs in my two nvidia graphics cards, and runs SIXTY TIMES FASTER [e.g. That 30 minutes becomes 30 SECONDS!] than it does in one of the CPU's cores! 
