I too have found that 333FSB is a stable OC. I can boot into windows at FSB 350 and www is OK but I ran DVDShrink and I crashed out and rebooted.

Here is my CPU-Z

My Settings:

BIOS 2103 (2004 gave me a CPU uCode error)

AI Overclocking set to: MANUAL

CPU Frequency : 333MhZ
DRAMM Frequency :800Mhz (1:1 according to CPUZ)

Performance Mode :Turbo
PCI Express Frequency : 100Mhz
PCI Clock Sync Mode : 33.33Mhz

Memory Voltage : 2.1v
CPU Vcore Voltage : 1.4 (1.37 in CPU-Z)
FSB Termination V : 1.4
MCH Chipset V : 1.65
ICH Chipset V : 1.2
--------------------------------------------------------

CPU Configuration

Microcode Update : Disabled
Max CPUID Value Limit : Disabled
Execute Disable Function : Disabled
CPU Internal Thermal Control : Disabled
Virtualization Technology : Disabled
Intel SpeedStep Technology : Disabled
--------------------------------------------------------

Advanced Chipset Settings (DDR2)

Configure DRAM Timing By SPD : MANUAL
DRAM CAS Latency : 4
DRAM RAS Precharge : 4
DRAM RAS To CAS Delay : 4
DRAM RAS Activate to Precharge Delay : 12
DRAM Write Recovery Time : 4

Hyper Path 3 : Disabled
DRAM Throttling : Disabled

COOLING: Nautilus 500 WC
Temps: 46C idle and 60C at 100% load

The above is stable but I will run orthos tonight.
I think that my Rev. C0 board is at its limit.

What do you think. Is it worth another board to push higher?
I was a bit disappointed since I was pushing 400FSB on my E6400 but then again this is a QUAD.

Anyone think that a P5B would yield a 4 GHz. clock?