ACFS is slower than Aix JFS2, poor performance

AIX  version: 6100-06-08-1216,hardware: ibm power 570

Processor Type: PowerPC_POWER6

Number Of Processors: 10

Processor Clock Speed: 4208 MHz

Memory Size: 40960 MB

oracle version: 11Gr2 11.2.0.3 RAC

A EMC storage CX240,  a LUN is used as ACFS，when we cp or tar some files, it's slow,only 46M/s

FileSystem                    KBPS     TPS   KB-R   KB-W    Open   Create   Lock

/test                             46.4K   11.6K  23.2K  23.2K      0      0       0

but if I use the same LUN as aix's JFS2 filesystem, the I/O will be 228M/s 

FileSystem                    KBPS     TPS   KB-R   KB-W    Open   Create   Lock

/gui                         228.8K   57.2K 114.4K 114.4K      0      0       0

is there  any method to tune the ACFS performance ?