SATA problems with 5.3Beta-7 amd AMD64

Are there any known unfixed problems with SATA disks and ICH5R (RAID not 
used) controller.

I have the following:
Supermicro  X6DVA-EG board with Intel E7320 chipset
2* Xeon 3GHz with EM64T
2* Seagate ST3120026AS 80GB SATA drives.
FreeBSD 5.3 Beta-7 AMD64

The machine hangs (actually the disk layer hangs) from time to time with 
a DMA read error. The machine is not in production but as it is now I 
have only console access to it for half and hour every evening. Maybe I 
should bring it home so I can have a good look at what is wrong with it.

What is the best (most supported) way to configure the SATA controller, 
I think it is in enhanced mode now, is this wrong?

I would be happy if we can solve this before 5.3 is released.

	/Martin