Many of us have switched from the TE to the TX and the TX is very decidedly faster. However, my initial experience was that the TX was a bit slower (no where near four times slower though) but my problem turned out to be that I had installed all the old apps from my TE on to the TX. Some were not compatible and caused the slow down.
My advice to you would be to do a hard reset (not simply delete third party apps) then measure the performance. If it is still slower, contact Palm and explain to them.