Seems raising CPU VTT from 1.4v to 1.5v helped but only in conjunction with raising NB volts from 1.55v to 1.65v. 345FSB seems fine so far.

Settings used:
AI Tuning: Manual
Nvidia GPU Ex: Disabled
LinkBoost: Disabled

FSB - Memory Clock Mode: Unlinked
x FSB - Memory Raio: N/A
FSB (QDR), Mhz: 1380 (means 345FSB)
Actual FSB (QDR), Mhz: 1380
MEM (DDR), Mhz: 805 (means 402mhz speeds)
Actual MEM (DDR), Mhz: 805

Vcore Voltage: 1.425 set (1.31v bios/1.30v windows idle/1.28v windows load - 0505 and higher bios fix the vcore issue but 0402 bios more stable for both my E6600/Q6600 cpus)
Memory Voltage: 2.000v
1.2v HT Voltage: 1.4v
NB Core Voltage: 1.65v
SB Core Voltage: 1.50v
CPU VTT Voltage: 1.5v
DDRII Controller Ref Voltage: AUTO
DDRII Channel A Ref Voltage: AUTO
DDRII Channel B Ref Voltage: AUTO

tCL (CAS Latency): 4
tRCD: 4
tRP: 4
tRAS: 12
Command Per Clock (CMD): 2 clock (2T)

Advance Memory Settings
tRRD: AUTO
tRC: AUTO
tWR: AUTO
tWTR: AUTO
tREF: AUTO
Async Latency: AUTO

CPU Spread Spectrum: Disabled
PCIE Spread Spectrum: Disabled
MCP PCIE Spread Spectrum: Disabled
SATA Spread Spectrum: Disabled
LDT Spread Spectrum: Disabled

CPU Internal Thermal Control: Disabled
Limit CPUID MaxVal: Disabled
Enhanced C1 (C1E): Disabled
Execute Disable Bit: Disabled
Virtualization Technology: Disabled
Enhanced Intel Speedstep Tech: Disabled
LDT Frequency: 5x

PCIEX16_1 Frequency (Mhz): 100
PCIEX16_2 Frequency (Mhz): 100
PCIEX16_3 Frequency (Mhz): 100
SPP<->MCP Ref Clock, Mhz: 200


Quad threaded Prime95 v25.1 small FFTs loaded


Quad threaded Prime95 v25.1 small FFTs post load idle


Please note different room temps for the 9x336FSB vs 9x345FSB sessions.