Please help with OC'g -- thanks

[L33T]

Hey,

I'd like some help with OC'g my computer.

My specs are listed my sig, but for clarity, allow me to specify the items important to this post:
P4 3.0C
RAM: Kingston 512mb 2700 ValueRAM

My current OC is:
fsb: 250 (5:4)
CPU: 3.758 GHz, VCC[nominal] = 1.675, VCC[actual] = 1.62
RAM: 200.5 MHz = DDR400, 2.5/3/3/7, DDRVCC[nominal] = 2.70, DDRVCC[actual] = 2.70-2.72

Unfortunately, this OC isn't particularly stable. It does boot into WinXP, and allows me to watch Hitchcock's "The Birds", and play CS:S indefinitely. However, it will randomly freeze. Originally the voltage was set to 1.6500 nominal, and 1.6000 actual; I've just now set it to 1.675 nominal, 1.616 actual--hopefully this will stabilise things. At this point I have Prime95 running starting at 5:00AM...it'll run until 5:00pm...and I've gotta sleep soon.

Previously, I have the following checkpoints:

fsb 243 (CPU: 3.65 GHz) -- Prime95, 13 hrs stable
fsb 234 -- Prime95, 24 hrs stable

This is definitely not a temperature issue. At no point does the temperature rise above 60*C (conservative estimate, since I'm not awake to watch the temperature rise...and the room temperature does fluctuate during the nite, and can get pretty warm). Currently, the load temperature is 49.5*C. (This is a WC'd system...please see sig for specs).

Any suggestions are very much so appreciated. I'm trying to figure out if there's anything that I may have overlooked.

I'm hoping to reach 4.0GHz with this.

Thanks