Xorg/X11 driver Radeon: radeon vs. radeonhd, a mess!

On two boxes running FreeBSD 8.0-CURRENT/amd64 (both PCIe-basis) I
utilise AMD/ATi RV770LE and RV730 based graphicsadapter. Both machines
run the most recent FreeBSD 8.0-CURRENT and most recent X11 from ports
(with all the subsequent packages).
The box with the most powerful graphicsadapter is the lowest powerful
box, equipted with a UP kernel, single core CPU, PCIe 1.1. The GPU is a
RV770LE mounted on a MSI R4830T2D512, This box does only work properly
with driver 'radeon', using driver 'radeonhd' results in a missing
display adapter - means, driver connot find a valid graphics card.

On my lab's box, a 4-core SMP box with a more modern P35 chipset I
utilise a MSI R4760 graphics card, this uses a AMD/ATi RV730 chip as
GPU. This box does only run with 'radeonhd' in a propper manner, using
'radeon' craches the box when shutting down/resetting (kill -1)  Xorg
(server)  when rebooting or leaving windowmaker. Although  'radeonhd'
works and 'radeon' not, using 'radeonhd' renders X unusable. Window
movement is like a slideshow,  firefox seems to sleep randomly,
scrolling is a game for patient people. VESA driver is much faster than
'radeonhd' on this fast chipset!

Well, xf86-video-radeonhd is at revision 1.2.5 and this one is, when
believing what the Wiki says, under development and advisory of AMD
itself. Why is it so bumpy and unwilling to recognize an RV770LE
chipset? Does anyone has a hint or tip?

It feels like a mess having two ATI drivers each one following different
ways of development. What 'radeon' is capable of is missing in
'radeonhd' and vice versa.

Regards,
Oliver