Solution:

The PCA-6154 BIOS rev.1.11 does a little different to other boards. If you use on board VGA then the memory section C000h to CB00h will be occupyed by the decompress VGA BIOS. The system BIOS will be decompress to the F000h to FFFFh sigment. The memory sigment form CC00h to EFFFh is free to use. I had check with R&D engineer and use AMIDIAG rev. 5.11 test to proof it. A important thing is that if you plug in a VGA card, BIOS will release C800h to CBFF out. This means the SiS 5598 VGA function neeed to use this segment. So if your customer need to use C800h to CC00h. Please plug in a CPU card (I use PCA-6653) and on board VGA function will disable automatically. Since now system use other VGA chip, the memory segment C800 to CC00 will be released.