Hi Paul! 
I guess I should have mentioned that I had the card in the A1200 for a couple of weeks with no software installed (performed no better than my ACA1232@33MHz - which motivated me). I had run SysInfo a few times and noticed that Data Burst was never ON. I could turn it on with a button in SysInfo but was never sure if it was actually ON until I read that you can control many functions of the CPU at the command line. That was actually kind of fun as I could toggle the Data Burst with SysInfo and could immediately see the result by running the CPU using CLI. Typing "CPU ?" showed me all the CPU arguments available. AmigaOS is so cool. So, I added C:CPU DataBurst >NIL: in the startup-sequence which turns it on at startup (verified with SysInfo). Problem solved.
MIPS.... ahhh, that brings me to another little problem. I run WB in Super Plus mode and SysInfo is the only program that won't cooperate at that screen resolution. The program is shifted about 30% to the left and top of the screen which prevents me from seeing the mips calculation. I had this problem with a few other programs. However, I was able to correct those telling the offending program what screen res to use in their screen menus and hit save. SysInfo has no way to do that - I read the guide to see if I could some how force SysInfo to use Super Plus (800x600) but can't figure it out. Is there a way, maybe in SysInfo's "Tool Type" to do that? Would be great if I could. Then I could tell you the MIPS of the board! 
I got the wrong end of the stick, my mistake. I read it as in you had problems booting with data burst enabled. I have the ACA1232 @ 33MHz which uses the ACATune command to enable all the features, but alas, it's sitting in it's box currently. Your mips rating sounds about right for that card so that's good news. I'll overclock my card one day when I get around to it!
