after running a speed test with Ati Tray Tools I can run the card at the XT speeds without any issues, but I also found out that I can use ATI tools to create a profile and run it at startup. So that's what I've done, much safer and easier than a BIOS flash and waaayyy more reversable.
Considerable improvement over the 5700U, AquaMark 2003 score has jumped from 27,000 to 35,300! Woot! and HL2 mods all in DX9 - I might just play HL2 again and start Lost Coast, with a little bit of HDR - woot!
I'm also considering buying X-plane, having had MS FS 2002 for some time and being an old X-plane fan and user, I'm very impressed with the 8.40 demo and the price is just amazing!