(In reply to comment #13)
> Try comparing the following registers between fglrx and radeon:
> 
difference:

left (fglrx) right(rad)

GB_ADDR_CONFIG
-0x98F8 0x02010002 (33619970)
+0x98F8 0x02010001 (33619969)

CGTS_SYS_TCC_DISABLE
-0x3F90 0x00000000 (0)
+0x3F90 0xff000000 (-16777216)

CGTS_TCC_DISABLE
-0x9148 0x00000000 (0)
+0x9148 0xff000000 (-16777216)

CGTS_USER_SYS_TCC_DISABLE
-0x3F94 0x00000000 (0)
+0x3F94 0xff000000 (-16777216)

CGTS_USER_TCC_DISABLE
-0x914C 0x00000000 (0)
+0x914C 0xff000000 (-16777216)

PA_SC_FORCE_EOV_MAX_CNTS
-0x8B24 0x00ff0fff (16715775)
+0x8B24 0x00ff3fff (16728063)

SMX_DC_CTL0
-0xA020 0x00158009 (1409033)
+0xA020 0x00020009 (131081)

SPI_CONFIG_CNTL_1
-0x913C 0x00000004 (4)
+0x913C 0x00000000 (0)

VGT_CACHE_INVALIDATION
-0x88C4 0x000000c1 (193)
+0x88C4 0x000000c2 (194)