Hi Holmer/Rob,

Glad to report back that my system is happily running with e8600@4.0GHz. Believe the reason for the previous freeze when window startup is due to some error in the CCC profiles which I created to manage the heat from the 4870X2 Xfire. My settings are as follows:

-P5e64 ws evolution BIOS 0601
-e8600 with xigamatek 964 hsf
-Corsair TW3X4G1600C9DHX 1600MHz 4GB Kit DDR3
-PowerColor 4870X2 CrossFire
-Aerocool Horsepower 1020W

Ai Overclock Tuner: Manual
CPU Ratio setting: 10.0
FSB strap to North Bridge: 333
FSB Frequency: 400
PCIE Frequency: 100
DRAM Frequency: 1600
DRAM Command rate: 1N

DRAM Timing Control: Manual
1st Information:
CAS Latency 7
RAS to CAS Delay 7
RAS to PRE Time 7
RAS ACT Time 20
RAS to RAS Delay A
REF Cycle Time A
Write Recovery Time A
READ to PRE Time A
2nd Information:
Read to Write Delay (S/D) A
Write to Read Delay (S) A
Write to Read Delay (D) A
Read to Read Delay (S) A
Read to Read Delay (D) A
Write to Write Delay (S) A
Write to Write Delay (D) A
3rd Information:
Write to PRE Delay A
Read to PRE Delay A
PRE to PRE Delay A
All PRE to ACT Delay A
All PRE to REF Delay A
DRAM Static Read Control Disable
DRAM Static Write Control Disable

DRAM Skew Control: A

Ai Clock Twister: A

Ai Transaction Booster: A

CPU Voltage: 1.33XX (CPUID at 1.304v)
CPU GTL Voltage Reference A
CPU PPL Voltage 1.52
FSB Termination Voltage 1.32
DRAM Voltage 1.76
NB Voltage Auto or 1.35
NB GTL Voltage Reference A
SB Voltage A
Clock Over-Charging Voltage A

Load-Line Calibration Normal
CPU Spread Spectrum Disable
PCIE Spread Spectrum Disable
CPU Clock Skew Delay 100ps
NB Clock Skew Delay 100ps