I'm sure every laptop is different, but mine works best with BOTH a single CPU client and the GPU client. If I only use one single core client (Vista seems ot split the load at 50% each core) the fan will ramp up and down in speed trying to cool the laptop. It goes from almost off to about 70% speed. This results in CPU temps cycling from 50 to 65C. When I am running just the GPU client things are worse (at least from a temperature cycling). The fan will go from off to nearly full speed. That results in the GPU temp swinging from 45 to 70C. However, with both the GPU running at 100% and the CPU client at 70% (thats 35% a core) the whole thing stablizes at 55C and the fan runs at a constand speed. Compare this to the short time I ran the multicore SMP client and the CPU temp ran at 70C and the fan was full speed.
To hypothisize a bit, The M8600GT GPU chip does not fluctuate in its power use as much as the CPU does. Running the GPU at full is not that bad. It is only when the CPU use goes to 100% that the laptop feels like its going to melt. This is also my experience when playing games. CPU use is low the game is GPU bound and the laptop is warmish. The time or two I have used the laptop to compress video has resulted in the laptop feeling hot, and the fan spinning up to what I think is 100% speed.
I think I would be more inclined to fold on the laptop if the WU were smaller or the dead lines shorter. It takes about 30 minutes for a percent on the GPU and 35 to 45 minutes for the CPU. In order to see results at that speed it needs to folding 24/7. That really is not how I use the laptop. If the time frame was more like 8 or 16 hours it would apeal to me more. However, the single core CPU client does have the advantage of long deadlines, so with normal laptop use I might be able to make deadlines.
With the Desktop, I don't mind the 24/7 opperation. I used to leave it on, overnight just so it would perform its house cleaning. And if something burns up, it can be replaced cheeply. Heck as it is now, parts are just too old a long time before they burn up. I would almost welcome the chance replace a broken part.
[edit: attached sig