P5K-Dlx: CPU Voltage Reference & NB Voltage Reference effects on OC-ability

[XtremeTiramisu]

I've a specific question for all P5K-Dlx OC'ers:

I'm at the borderline of being stable - FSB470*8 @ 1.465v(Bios Set)
I left CPU Voltage Reference & NB Voltage Reference both at AUTO and CPU PLL voltage was at 1.5v.
Orthos stress cpu small fft failed after 7hrs and 30mins (Common rounding error, expected 0.5 and only 0.4 from one core.)

Right now, I've changed the CPU Voltage Reference & NB Voltage Reference both at x0.61 and upped the CPU PLL voltage from 1.5 to 1.6v. I'm trying to find out if I can get my current OC configuration stable without increasing the Vcore one notch up from the current 1.465v set in BIOS.

As you can see from the following detail configuration spec. My CPU PLL voltage is set at 1.6v (Options: 1.5, 1.6, 1.7, 1.8) and CPU reference voltage is set at x0.61 (Options: x0.67, x0.61, x0.57, x0.53). I'm wondering if the cpu reference voltage should be set to corresponding CPU PLL voltage? (ie. CPU PLL Voltage 1.5v = Auto/x0.67, 1.6v = x0.61, and so on. I've being gather infos from various members on various forums. I normally see CPU PLL voltage set at 1.5v and CPU reference voltage set at AUTO or x0.61 at higher FSB (470+)

My SB voltage is set at 1.2v and the corresponding NB reference voltage is set at x0.61. P5K-Dlx owners has found there's a correlation in SB voltage/NB reference voltage with Ram's overclocking-ability. My Rams seem to be stable under memtest for a few hours at current configuration (please see table below).

I'd think it's just the CPU compartment that's not 100% fully stable. Orthos small fft is currently running in green at 3 hrs 44 mins as of now after I've adjusted the CPU reference voltage/NB reference voltage. I hope this will stabilize my OC with the rest of my other configurations(please see table below) for 8hrs +

Please share your suggestions and give out some pointers that would aid in my current situation

JumperFree Configuration Settings
AI Overclocking: Manual
CPU Ratio Control: Manual
- Ratio CMOS Setting: 8
FSB Strap to Northbridge: 266
FSB Frequency: 470
PCI-E Frequency: 103
DRAM Frequency: DDR2-1175
DRAM Command Rate: 2T
DRAM Timing Control: Manual
CAS# Latency: 5
RAS# to CAS# Delay: 5
RAS# Precharge: 4
RAS# Activate to Precharge: 9
TWR: 3
TRFC: 25
TWTR: 3
TRRD: 3
TRTP: 6
DRAM Static Read Control: ENABLE

Transaction Booster: AUTO
Boost Level: (only displays when Transaction Booster is set to Disable or Enabled)
Clock Over-Charging Mode: AUTO

CPU Spread Spectrum: Disabled
PCIE Spread Spectrum: Disabled

CPU Voltage: 1.4650
CPU Voltage Reference: x0.61
CPU Voltage Damper: Enabled
CPU PLL Voltage: 1.6
DRAM Voltage: 2.2
FSB Termination Voltage: 1.40
North Bridge Voltage: 1.55
North Bridge Voltage Reference: x0.61
South Bridge Voltage: 1.2

Advance CPU Settings
CPU Ratio Control: Manual
- Ratio CMOS Setting: 8
C1E Suppport: Disabaled
Max CPUID Value Limit: Disabaled
Vanderpool Technology: Disabaled
CPU TM Function: Disabaled
Execute Disable Bit: Enabled
PECI: Enabled

USB Configuration
USB Functions: Enabled
Legacy USB Support: Disabled (need to enable it to detect USB flash drives)