You're using IDEFIX!
2.1MB / Sec is about the max you'll get out of the standard A1200 IDE.
If you had read all posts, then you've had noticed that I also did tests WITHOUT IDE-Fix!
Besides that, both HD and CF had benefit from the faster IDE-Fix adapter. So, it doesn't make any difference.
And 2.1MB isn't the max I get out of the standard A1200 IDE port. My other A1200 with Blizzard1230IV (WITHOUT IDE-Fix) and 2GB HD reaches a speed of 2.8MB p/s. Heck, even my A600/030 with 1GB HD reaches 2,6MB p/s!
I think it all comes down on what type/brand HD/CF and (important) CPU you use.