Transcoding question

I'm not sure whats going on here. I've began editing some projects in Final Cut ProX. My workflow is: copying all of my Canon 5D MarkII footage to a separate hard drive, which is my backup of the original files. From that hardDrive, I import all of the files, with transcode checked. Editing has been OK, but bigger projects are becoming very slow. I just noticed now, however, that when I click on the events info, they are appearing as H.264 files, and not proRes! It seems like Final cut pro is using my original files and not the transcoded ones which are in the high quality media folder...Is this normal? Am I missing something. I thought fcp would be automatically using the high quality media... Or does it just appear that way in the info window...ANy advice??

Thanks.