I'm trying to get to 500 fsb stable on my P5Q Pro but I'm stumped and in need of some help to steer me in the right direction. I'm running an E8400, CO revision level, with 2 gb Transcend AxeRam DDr2 6400 (D9). I've been able to get the CPU to go 9x445, 8.5x470, and now 8x490 completely stable, generally needing core voltage 1.36-1.376v in CPUz, 1.38-1.40v in BIOS. I've had the ram up to 1117 stable, or even higher, using 5-5-5-15 timings. The best I've been able to get it to do is 940 with 4-4-4-12 timings. I'm using Ket's modded BIOS 1307 for the P5Q Pro.

The problem I'm having is I'm fine at 490x8, but when I crank it up to 500x8 I get blue screens, instant prime blend test failures, and general instability. I have noticed it will pass small ffts for a while though.
I'm especially having a hard time figuring out where to set the FSB and NB voltages because I don't know where the BIOS puts them at when set to AUTO to use as a starting point for reference. Basically its been nothing more than a shot in the dark so far trying to figure out these two settings.

Here are my current BIOS settings, any help would be appreciated.

CPU Ratio: 8.0
FSB Freq: 490
FSB Strap: Auto
PCI-E: 101
DRAM Freq: 981
DRAM Timing: Manual

Timings 5-5-5-15, others AUTO

DRAM Static Read Ctrl: Disabled
DRAM Read Training: Disabled
Mem OC Charger: Enabled
AI Clock Twister: Moderate
AI Transaction Booster: Manual, PL 10, All Pull ins enabled

CPU Voltage: 1.40
CPU GTL Voltage Ref: Auto
CPU PLL Voltage: 1.56
FSB Termination V: 1.32
DRAM Voltage: 2.20
NB Voltage: 1.34
SB V: Auto
PCIE V: Auto