That CPU utilization is higher than normal for the Touch Diamond. TouchFLO 3D does use more memory but that's high (assuming no programs are running in the background-- if they are, then all bets are off).
For the default browser setting, you'll need to edit the registry. I believe it should be in the following key: HKEY_LOCAL_MACHINE\Software\Microsoft\Shell\Rai\: DEFBROWSER
use these values: 0 = Internet Explorer 1 = \Windows\iexplore.exe\
Not sure if you're comfortable downloading, installing and using a registry editor on the Diamond. But it should do the trick from what I recall. That way when you click on links in email and etc. it should launch IE. I'm not sure if this will change the default browser in the TouchFLO 3D web tab though.
-------------------- Lisa Gade Editor in Chief, MobileTechReview