I increased the Tile Cache to 3GB from 1GB and see the exact same usage profile Unfortunately, gimp has a hard limit at 3, so I can't test further.

I also got a gadget that watches all 4 cores and the RAM, and it is using all 4, though one seems to be maxing while the others aren't working nearly as hard (~ 90%,15%, 20%, 40% .... it fluctuates pretty wildly but that's probably a good average). I did see the total use of the processor peak at 48%, and RAM actually hit 53%.

I looked around for a vista-choking-resources solution, and basically found a whole lot of repetitive "it's only using that much because it only NEEDS to use that much" ... which I think is crap when it takes 15 minutes to finish a shaped gradient (while using less than half of the available juice). It doesn't seem to be fixable though, so I guess I'm just going to shrink the map.

How sad.