DRAM Termination and DRAM Ref, what exactly they do?

I'm working on my OC 500x8.5 Q9550, and it will freeze hyperpi if I leave the DRAM Termination/Ref on Auto, If I change them to Normal, Hyperpi will pass normally, is that because my ram or the Auto settings put wrong values?

This is with Mushkin 4GB DDR2 1066

current settings:

Robust Graphics Booster.........................[ Auto ]
CPU Clock Ratio.................................[ 8.0 ]
Fine CPU Clock Ratio............................[ +0.5 ]
CPU Frequency............................[ 500x8.5 ]

******Clock Chip Control******

CPU Host Clock Control..........................[ Enabled ]
CPU Host Frequency (Mhz)........................[ 500 ]
PCI Express Frequency (Mhz).....................[ 100 ]
C.I.A 2.........................................[ Disabled ]

******Advanced Clock Control******

CPU Clock Drive.................................[ 900mv ]
PCI Express Clock Drive.........................[ 900mv ]
CPU Clock Skew..................................[ 0ps ]
MCH Clock Skew..................................[ 0ps ]

******DRAM Performance Control******

Performance Enhance.............................[ Turbo ]
Extreme Memory Profile (X.M.P)..................[ Auto ]
(G) MCH Frequency Latch.........................[ Auto ]
System Memory Multipler.........................[ 2.00D ]
Memory Frequency 1066...........................[ 1000 ]
DRAM Timing Selectable..........................[ Manual ]

CAS Latency Time................................[ 5 ]
tRCD............................................[ 5 ]
tRP.............................................[ 5 ]
tRAS............................................[ 15 ]

******Motherboard Voltage Control******

Load-Line Calibration...........................[ Enabled]
CPU Vcore [ 1.1875 ]...................[ 1.33750 ]
CPU Termination [ 1.20 ]...................[ 1.360 ]
CPU PLL [ 1.50 ]...................[ 1.500 ]
CPU Reference [ 0.760 ]...................[ 0.9xx] ET reports 0.785
MCH Core [ 1.100 ]...................[ 1.360 ]
MCH Reference [ 0.760 ]...................[ 0.9xx ] ET reports 0.800
MCH/DRAM Refernce [ 0.900 ]...................[ Auto ]
ICH I/O [ 1.500 ]...................[ 1.570 ]
ICH Core [ 1.100 ]...................[ Normal ]

DRAM Voltage [ 1.800 ]...................[ 2.060 ]
DRAM Termination [ 0.900 ]...................[ Normal ]
Channel A Ref [ 0.900 ]...................[ Normal ]
Channel B Ref [ 0.900 ]...................[ Normal ]
This settings pass, but I set DRAM Termination to Auto/ Channel A\B Ref to Auto, it will freeze the PC just after 2 min with Hyperpi