Forgive me, but I'm not exactly sure how this works. As far as I can tell, the add-on memory for the Curve is only used for storage--photos, mp3s, etc. When I install an ap, it goes to the Curve's core memory, which can't be upgraded. Which means that adding more storage memory won't speed up the Curve's OS ... Do I have that right?
Assuming you have sufficient file free memory, the performance of your Curve will be based on the resources required by certain apps. I used some animated themes for a while, and they brought my Curve to it's knees. Another example is Slacker, which affects my performance.