Additionally, software like Easy CD Creator just doesn't drive the burner at the speed it can do. Roxio are more concerned, I think, about getting the burn fail ratio down, not in how fast you get the burner to write.
If you really wanna see if your drive can burn at its max speed, I recommend trying to free cdrecord command line utility under linux, in which you explicitly state the burning speed, as far as I recall. Then, if you use a CD that can handle being written at that speed, and then write the CD and it reads in your CD-ROM drive, then you know everything is fine.