Doing a big (800+) synth today, an it takes forever..
But that was expected, but it only uses 50% of my cpu (amd dualcore), and only 50% on each core.
Is it on my end the problem is, or is dualcore not supported?
I don't really have an answer, but for the 800+ image synths I've done it hasn't been an issue, since uploading the pictures themselves always seems to take longer than the number crunching. And uploads should (SHOULD!) use very little CPU at all.
I've also got a dual core AMD, so I'm curious what the answer is.
Some of the synthing process will take advantage of every core available, but some of the process can only use one core. If you're really interested in the details, create a synth with at least as many photos as you have cores, then watch the CPU utilization and look at the messages in the status bar on the synther.
I use Intel I7-920, it seem can advantage of every core available.
You can always start Task Manager, go to the 'Processes' tab, and set PSWebClient.exe to 'High' priority. That ought to suck the life right out of your CPU. =]