If it is not uncomfortable to the touch, then it is probably not an issue.
If memory serves (because it has been awhile since I brought the TC1100 up to a gig) it may be running a little warmer than before the upgrade, but not so much that it caused alarm or discomfort.
I have been working with my TC1100 in hand for two hours. Screen up full, wireless on, default processor speed for battery profile.
While it is warm, it is not at all uncomfortable
I am running with 1 gigabyte of RAM.
512 stock 512 Kingston
Is there anything else besides the additional ram that could be raising the heat?
charging the battery?
running at "full power"?
running CPU intensive tasks?
Since my original posting I decided to charge the battery, and it is not noticeably warmer.