I found only this:
Here is said that 890GX will run with HD 5450:
http://hothardware.com/articles/AMD-890GX-SB850-Motherboard-Chipset-Debut/
Here it is tested:
http://en.inpai.com.cn/doc/enshowcont.asp?id=7590&pageid=6720
*edit*
Here in compatibility chart 890GX is mentioned but still without 5000 series cards:
http://sites.amd.com/us/game/technology/Pages/crossfirex.aspx
I hope it helps
Thanks for that and according to the benchmark tests, the 5450 is at least one of the cards that works with the hybrid feature. i just sent a support email to amd and hopefully will get a list of ALL 'applicable' cards. i wish to buy the one card that would max out the boards potential. maybe the 5450 is the one; i'd like to be sure.
thanks again; i appreciate you for helping me out.